PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
SEPA
December 2023
United States Office of Chemical Safety and
Environmental Protection Agency Pollution Prevention
Draft Risk Evaluation for
Tris(2-chloroethyl) phosphate (TCEP)
Systematic Review Supplemental File:
Data Quality Evaluation Information for
Human Health Hazard Animal Toxicology
CASRN: 115-96-8
December 2023
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
This supplemental file contains information regarding the data quality evaluation results for data sources that met the PECO
screening criteria for the Draft Risk Evaluation for Tris(2-chloroethyl) phosphate (TCEP) and were used to characterize human
health hazard. EPA conducted data quality evaluation based on author-reported descriptions and results; additional analyses
(e.g., statistical analyses performed during data integration into the risk evaluation) potentially conducted by EPA are not
contained in this supplemental file. EPA used the TSCA systematic review process described in the Draft Systematic Review
Protocol Supporting TSCA Risk Evaluations for Chemical Substances (also referred to as '2021 Draft Systematic Review
Protocol'). Any updated steps in the systematic review process since the publication of the 2021 Draft Systematic Review
Protocol are described in the Systematic Review Protocol for the Draft Risk Evaluation for Tris(2-chloroethyl) phosphate
(TCEP).
Page 2 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Table of Contents
Table of Contents
HERO ID
Reference
Page
Tris(2-chloroethyl) phosphate (TCEP)
Acute (less than or equal to 24 hr)
6311026
Confidential, (1973). Toxicology laboratory report - tris (2-chloroethyl) phosphate.
656590
Sprague, G. L., Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame
retardants in hens. Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3):507-518.
11
107658
Tilson, H. A., Veronesi, B., Mclamb, R. L., Matthews, H. B. (1990). Acute exposure to tris(2-chloroethyl)phosphate produces hippocampal
neuronal loss and impairs learning in rats. Toxicology and Applied Pharmacology 106(2):254-269.
13
5469219
Umezu, T., Yonemoto, J., Soma, Y., Suzuki, T. (1998). Tris(2-chloroethyl)phosphate increases ambulatory activity in mice: pharmacologi-
cal analyses of its neurochemical mechanism. Toxicology and Applied Pharmacology 148(1): 109-116.
15
Short-term (>1-30 days)
6311010
FDRL, (1972). Cholinesterase studies on rats and rabbits with Olin's intermediate for Chemical 58981.
17
790471
Hazleton Laboratories, (1983). Screening of priority chemicals for potential reproductive hazard (final report) with attachments and cover
sheet.
19
5469669
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and
B6C3F1 Mice (Gavage Studies). National Toxicology Program Technical Report Series 391:1-233.
24
5469568
Sala, M., Gu, Z. G., Moens, G., Chouroulinkov, I. (1982). In vivo and in vitro biological effects of the flame retardants tris(2,3-
dibromopropyl) phosphate and tris(2-chlorethyl)orthophosphate. European Journal of Cancer & Clinical Oncology 18(12): 1337-1344.
62
656590
Sprague, G. L., Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame
retardants in hens. Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3):507-518.
64
5469208
Taniai, E., Hayashi, H., Yafune, A., Watanabe, M., Akane, H., Suzuki, K., Mitsumori, K., Shibutani, M. (2012). Cellular distribution of cell
cycle-related molecules in the renal tubules of rats treated with renal carcinogens for 28 days: relationship between cell cycle aberration
and carcinogenesis. Archives of Toxicology 86(9): 1453-1464.
72
5469521
Taniai, E., Yafune, A., Hayashi, H., Itahashi, M., Hara-Kudo, Y., Suzuki, K., Mitsumori, K., Shibutani, M. (2012). Aberrant activation
of ubiquitin D at G2 phase and apoptosis by carcinogens that evoke cell proliferation after 28-day administration in rats. Journal of
Toxicological Sciences 37(6): 1093-1 111.
74
Subchronic (>30-91 days)
4199395
Chen, G., Jin, Y., Wu, Y., Liu, L., Fu, Z. (2015). Exposure of male mice to two kinds of organophosphate flame retardants (OPFRs) induced
oxidative stress and endocrine disruption. Environmental Toxicology and Pharmacology 40(1): 310-318.
76
Page 3 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Table of Contents
5469245
Yang, W., Zhao, F., Fang, Y., Li, L., Li, C., Ta, N. (2018). lH-nuclear magnetic resonance metabolomics revealing the intrin-
sic relationships between neurochemical alterations and neurobehavioral and neuropathological abnormalities in rats exposed to tris(2-
chloroethyl)phosphate. Chemosphere 200:649-659.
80
Chronic (>91 days)
5469641
Matthews, H. B., Dixon, D., Herr, D. W., Tilson, H. (1990). Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate admin-
istration results in lesions in the rat hippocampus. Toxicology and Industrial Health 6(1): 1-15.
82
5469669
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and
B6C3F1 Mice (Gavage Studies). National Toxicology Program Technical Report Series 391:1-233.
135
5469568
Sala, M., Gu, Z. G., Moens, G., Chouroulinkov, I. (1982). In vivo and in vitro biological effects of the flame retardants tris(2,3-
dibromopropyl) phosphate and tris(2-chlorethyl)orthophosphate. European Journal of Cancer & Clinical Oncology 18(12): 1337-1344.
243
Reproductive/Developmental
790471
Hazleton Laboratories, (1983). Screening of priority chemicals for potential reproductive hazard (final report) with attachments and cover
sheet.
245
3008543
Moser, V. C., Phillips, P. M., Hedge, J. M., McDaniel, K. L. (2015). Neurotoxicological and thyroid evaluations of rats developmentally
exposed to tris(l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP). Neurotoxicology and Teratology
52(Pt B):236-247.
247
10603716
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
260
Page 4 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 6311026 Table: 1 of 3
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Confidential, (1973). Toxicology laboratory report - tris (2-chloroethyl) phosphate.
Irritation
Skin and Eye Irritation.
Acute (less than or equal to 24 hr) Single dose
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
6311026
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
Test substance was identified as tris (2-chloroethyl) phosphate (CASRN 115-96-8).
Metric 2:
Test Substance Source
Low
The test substance source was not reported.
Metric 3:
Test Substance Purity
Low
Purity of test substance was not reported.
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
N/A
Not necessary for skin and eye irritation testing. The untreated eye served as the control
in the eye irritation study.
Metric 5:
Positive Controls
N/A
Positive Controls do not apply to this study.
Metric 6:
Randomized Allocation of Animals
N/A
Not necessary for this study type.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Low
Information on preparation and storage of the test substance was not reported.
Substance
Metric 8:
Consistency of Exposure
High
Details of exposure administration were reported and exposures were administered
Administration
consistently across study groups.
Metric 9:
Reporting of Doses/Concentrations
Low
For the eye irritation study, 0.1 ml of test substance was instilled into the eye, while 0.5
ml of test substance was applied to the skin for the dermal irritation study. The concen-
tration of TCEP in the applied doses was not reported.
Metric 10:
Exposure Frequency and Duration
High
Exposure frequency and duration were sufficient for this study.
Metric 11:
Number of Exposure Groups and
N/A
The goal of this study was not to determine a dose-dependent effect.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
The exposure routes and methods were appropriate for this study.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Low
New Zealand rabbits weighing 1.6-2.1 kg were used. The sex and source of the test
animals was not reported
Metric 14:
Adequacy and Consistency of Animal
Low
Husbandry conditions were not reported.
Husbandry Conditions
Metric 15:
Number of Animals per Group
Medium
Number of animals per group were sufficient for this study.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
Outcome assessment methodology was adequate for this study.
Metric 17:
Consistency of Outcome Assessment
High
Details of the outcome assessment protocol were reported and outcomes were assessed
consistently.
Continued on next page ...
Page 5 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 6311026 Table: 1 of 3
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Confidential, (1973). Toxicology laboratory report - tris (2-chloroethyl) phosphate.
Irritation
Skin and Eye Irritation.
Acute (less than or equal to 24 hr) Single dose
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
6311026
Domain
Metric
Rating
Comments
Metric 18:
Sampling Adequacy
High
Reported information indicates the study used adequate sampling.
Metric 19:
Blinding of Assessors
N/A
Not necessary for this study type.
Metric 20:
Negative Control Response
N/A
Negative controls are not necessary for this study type.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
Low
Confounding variables (body weight, food/water intake) were not reported.
and Procedures
Metric 22:
Health Outcomes Unrelated to
Low
4 out of 6 rabbits died during the dermal irritation study. Cause of death was not de-
Exposure
termined and it is unclear if mortality was due to the test substance or something (e.g.,
infection) unrelated to exposure.
Metric 23:
Data Presentation and Analysis
N/A
Statistical analysis was not possible, as only a single treatment group was included in the
eye and skin irritation tests.
Metric 24:
Reporting of Data
High
Quantitative data was reported for the skin irritation study. For eye irritation, study
authors clearly state that no evidence of irritation was observed.
Overall Quality Determination
Medium
Page 6 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 6311026 Table: 2 of 3
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Confidential, (1973). Toxicology laboratory report - tris (2-chloroethyl) phosphate.
Mortality
mortality
Acute (less than or equal to 24 hr) Single dose
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
6311026
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
Test substance was identified as tris (2-chloroethyl) phosphate (CASRN 115-96-8).
Metric 2:
Test Substance Source
Low
The test substance source was not reported.
Metric 3:
Test Substance Purity
Low
Purity of test substance was not reported.
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
N/A
Not necessary for skin and eye irritation testing. The untreated eye served as the control
in the eye irritation study.
Metric 5:
Positive Controls
N/A
Not necessary for this study type.
Metric 6:
Randomized Allocation of Animals
N/A
Not necessary for this study type.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Low
Information on preparation and storage of the test substance was not reported.
Substance
Metric 8:
Consistency of Exposure
High
Details of exposure administration were reported and exposures were administered
Administration
consistently across study groups.
Metric 9:
Reporting of Doses/Concentrations
Low
For the eye irritation study, 0.1 ml of test substance was instilled into the eye, while 0.5
ml of test substance was applied to the skin for the dermal irritation study. The concen-
tration of TCEP in the applied doses was not reported.
Metric 10:
Exposure Frequency and Duration
High
Exposure frequency and duration were sufficient for this study.
Metric 11:
Number of Exposure Groups and
N/A
The goal of this study was not to determine a dose-dependent effect.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
The exposure routes and methods were appropriate for this study.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Low
New Zealand rabbits weighing 1.6-2.1 kg were used. The sex and source of the test
animals was not reported
Metric 14:
Adequacy and Consistency of Animal
Low
Husbandry conditions were not reported.
Husbandry Conditions
Metric 15:
Number of Animals per Group
Medium
Number of animals per group were sufficient for this study.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
Outcome assessment methodology was adequate for this study. Animals were observed
for mortality.
Metric 17:
Consistency of Outcome Assessment
High
Outcome of study assessment is adequate for this study.
Metric 18:
Sampling Adequacy
High
All treated animals were observed for mortality.
Continued on next
page...
Page 7 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 6311026 Table: 2 of 3
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Confidential, (1973). Toxicology laboratory report - tris (2-chloroethyl) phosphate.
Mortality
mortality
Acute (less than or equal to 24 hr) Single dose
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
6311026
Domain
Metric
Rating
Comments
Metric 19:
Blinding of Assessors
N/A
Not necessary for this study type.
Metric 20:
Negative Control Response
N/A
Negative controls are not necessary for this study type.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
Low
Confounding variables may have played a factor because of the lack of information on
and Procedures
animals.
Metric 22:
Health Outcomes Unrelated to
Low
4 out of 6 rabbits died. Cause of death was not determined and it is unclear if mortality
Exposure
was due to the test substance or something (e.g., infection) unrelated to exposure.
Metric 23:
Data Presentation and Analysis
N/A
Statistical analysis was not possible, as only a single treatment group was included in the
eye and skin irritation tests.
Metric 24:
Reporting of Data
Medium
Study authors reported that 4 out of 6 rabbits died following the 4-hr dermal exposure.
Animals were observed for up to 96-hours, however, study authors do not report the
specific timing of when each rabbit died.
Overall Quality Determination
Medium
Page 8 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 6311026 Table: 3 of 3
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Confidential, (1973). Toxicology laboratory report - tris (2-chloroethyl) phosphate.
Neurological/Behavioral
Narcosis and paralysis.
Acute (less than or equal to 24 hr) Single dose
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
6311026
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
Test substance was identified as tris (2-chloroethyl) phosphate (CASRN 115-96-8).
Metric 2:
Test Substance Source
Low
The test substance source was not reported.
Metric 3:
Test Substance Purity
Low
Purity of test substance was not reported.
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
N/A
Not necessary for skin and eye irritation testing. The untreated eye served as the control
in the eye irritation study.
Metric 5:
Positive Controls
N/A
Not necessary for this study type.
Metric 6:
Randomized Allocation of Animals
N/A
Not necessary for this study type.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Low
Information on preparation and storage of the test substance was not reported.
Substance
Metric 8:
Consistency of Exposure
High
Details of exposure administration were reported and exposures were administered
Administration
consistently across study groups.
Metric 9:
Reporting of Doses/Concentrations
Low
For the eye irritation study, 0.1 ml of test substance was instilled into the eye, while 0.5
ml of test substance was applied to the skin for the dermal irritation study. The concen-
tration of TCEP in the applied doses was not reported.
Metric 10:
Exposure Frequency and Duration
High
Exposure frequency and duration were sufficient for this study.
Metric 11:
Number of Exposure Groups and
N/A
The goal of this study was not to determine a dose-dependent effect.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
The exposure routes and methods were appropriate for this study.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Low
New Zealand rabbits weighing 1.6-2.1 kg were used. The sex and source of the test
animals was not reported
Metric 14:
Adequacy and Consistency of Animal
Low
Husbandry conditions were not reported.
Husbandry Conditions
Metric 15:
Number of Animals per Group
Medium
Number of animals per group were sufficient for this study.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Low
Study authors state that eyes were scored for irritation every 24, 48 and 72 hours. Au-
thors do not state how frequently animals were observed for signs of narcosis and paral-
ysis.
Continued on next page ...
Page 9 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 6311026 Table: 3 of 3
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Confidential, (1973). Toxicology laboratory report - tris (2-chloroethyl) phosphate.
Neurological/Behavioral
Narcosis and paralysis.
Acute (less than or equal to 24 hr) Single dose
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
6311026
Domain
Metric
Rating
Comments
Metric 17:
Consistency of Outcome Assessment
Low
Details regarding the execution of the study protocol for outcome assessment were not
reported. Study authors do not state when or how frequently animals were observed for
signs of narcosis.
Metric 18:
Sampling Adequacy
High
Reported information indicates the study used adequate sampling.
Metric 19:
Blinding of Assessors
N/A
Not necessary for this study type.
Metric 20:
Negative Control Response
N/A
Negative controls are not necessary for this study type.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
Medium
Confounding variables (body weight, food/water intake) were not reported.
and Procedures
Metric 22:
Health Outcomes Unrelated to
Low
4 out of 6 rabbits died. Cause of death was not determined and it is unclear if mortality
Exposure
was due to the test substance or something (e.g., infection) unrelated to exposure.
Metric 23:
Data Presentation and Analysis
N/A
Statistical analysis was not possible, as only a single treatment group was included in the
eye and skin irritation tests.
Metric 24:
Reporting of Data
Low
Study authors reported that 4 out of 6 rabbits exhibited signs of narcosis and paralysis
following ocular exposure to the test substance. Study authors do not report the timing
of when these observations were made.
Overall Quality Determination
Low
Page 10 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Neurological/Behavioral
Inhibition of plasma cholinesterase. Inhibition of neurotoxic esterase
Acute (less than or equal to 24 hr) 1 dose
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
Medium
No CASRN was identified but the name is specific enough to identify the exact struc-
ture.
The manufacturer was identified and chemical structure is not variable.
There was no information on purity.
Metric 2:
Metric 3:
Test Substance Source
Test Substance Purity
High
Low
Domain 2: Test Design
Metric 4:
Metric 5:
Metric 6:
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
Low
Medium
Low
The controls received corn oil but the dosed group received the test substance neat.
TOCP was used as a positive control and is appropriate for this test.
The study did not mention random allocation of animals.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Substance
Medium
There was limited/no info on preparation/storage but the chemical was administered
neat; it appears to be stable; and it was a short term study so it is not expected to result
in substantial effects.
Metric 8:
Consistency of Exposure
Administration
Medium
Corn oil in negative control vs. none in dose groups may result in some differences but
not likely to be substantial given that this is an acute study.
Metric 9:
Reporting of Doses/Concentrations
High
Doses were identified as g/kg.
Metric 10:
Exposure Frequency and Duration
High
Exposure frequency and duration were appropriate to the test.
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
High
A limit test used a dose higher than required.
Metric 12:
Exposure Route and Method
High
The oral route was used and was acceptable.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Low
The source of the hens was not reported.
Metric 14:
Adequacy and Consistency of Animal
Medium
Most husbandry information was reported except humidity and whether the animals
Husbandry Conditions
were acclimatized before treatment (although the figure seems to indicate animals were
kept for several days before treatment).
Metric 15:
Number of Animals per Group
Low
The number of animals was not reported for the acute biochemical portion of the study.
Domain 5: Outcome Assessment
Continued on next page ...
Page 11 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 1 of 1
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Neurological/Behavioral
Inhibition of plasma cholinesterase. Inhibition of neurotoxic esterase
Acute (less than or equal to 24 hr) 1 dose
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Domain
Metric
Rating
Comments
Metric 16: Outcome Assessment Methodology Low
Metric 17: Consistency of Outcome Assessment Medium
Metric 18: Sampling Adequacy Low
Metric 19: Blinding of Assessors N/A
Metric 20: Negative Control Response Low
Several deviations from OECD TG 870.6100 (1998) were noted. The animals were
sacrificed at 24 hrs after treatment instead of 48 hrs. A non-tissue blank was not used for
the NTE assay. NTE was measured only in brains and not in the spinal cord. AChE was
taken from plasma and not the brain.
The NTE activity was measured 18-24 hrs after sacrifice, so there was some variation.
However, samples for both NTE and AChE were both taken at the same time for the
control and TCEP dose group.
No information on sampling (i.e., number of hens) was reported for the acute/
biochemical portion of the study.
Blinding of assessors is not considered necessary for the acute/biochemical portion of
the study because the measures are objective.
The authors note that mild adverse signs were noted after administration of corn oil in
the control group. Given that Marek's disease is related to the outcome of interest, it
is not clear whether it may have affected some outcomes; it is assumed chickens in all
groups may have been exposed to the virus that causes Marek's disease but the authors
don't clearly state this.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Medium It is unclear how deviations from the protocol and use of corn oil only may have affected
the outcome.
Medium Authors mention that the corn-oil treated hens (controls) may have had Marek's disease,
which effects the nerves and there were mild adverse effects directly after gavage of the
control group. It is assumed that all chickens were likely to have been exposed to the
virus that causes Marek's but the authors were not clear about that.
High Statistical methods were described.
High Both biochemical measures (NTE from brain and plasma AChE) were reported.
Overall Quality Determination
Medium
Page 12 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 107658 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Tilson, H. A., Veronesi, B„ Mclamb, R. L., Matthews, H. B. (1990). Acute exposure to tris(2-chloroethyl)phosphate produces hippocampal neuronal loss
and impairs learning in rats. Toxicology and Applied Pharmacology 106(2):254-269.
Neurological/Behavioral
TCEP treatment resulted in behavioral effects (convulsions) and histopathological changes in the hippocampus. The seizure-related and neurohistological
effects were significantly attenuated by pretreatment with atropine or chlordizepoxide, suggesting that the hippocampal damage was related to the seizure.
In a second experiment, rats were mildly impaired in the acquisition of a reference memory task in a water maze, however, rats were consistently impaired
in performing a repeated acquisition task in the water maze.
Acute (less than or equal to 24 hr) Acute oral (gavage)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
107658
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
The test substance was identified definitively by name.
Metric 2:
Test Substance Source
High
The source of the test substance was identified.
Metric 3:
Test Substance Purity
Low
Test substance purity was not provided.
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
High
This is a single dose study to structural and functional neurotoxic effects
Metric 5:
Positive Controls
N/A
A positive control was not included or needed.
Metric 6:
Randomized Allocation of Animals
Low
The study did not report how animals were allocated.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Medium
Preparation/administration of test substance is described, but storage is not reported
Substance
however the assay is a short-term study and therefore storage is unlikely to affect results.
Metric 8:
Consistency of Exposure
High
Exposures were administered consistently across study groups.
Administration
Metric 9:
Reporting of Doses/Concentrations
Medium
Only nominal doses were reported.
Metric 10:
Exposure Frequency and Duration
High
Single exposure was reported.
Metric 11:
Number of Exposure Groups and
Low
Only a single treated group was used.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
The route and method of exposure were reported and were suited to the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Medium
Characteristics including starting body weight were not reported, but are unlikely to
have a substantial impact on results.
Metric 14:
Adequacy and Consistency of Animal
High
All husbandry conditions were reported (e.g., temperature, humidity, light- dark cycle,
Husbandry Conditions
diet, water availability) and were adequate and the same for control and exposed popula-
tions, such that the only difference was exposure.
Metric 15:
Number of Animals per Group
Low
The number of animals per study group was not clearly reported for all parameters. It
appears to range from 6-8 animals.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
The outcome assessment methodology addressed the intended outcomes of interest.
Continued on next
page...
Page 13 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 107658 Table: 1 of 1
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Tilson, H. A., Veronesi, B„ Mclamb, R. L., Matthews, H. B. (1990). Acute exposure to tris(2-chloroethyl)phosphate produces hippocampal neuronal loss
and impairs learning in rats. Toxicology and Applied Pharmacology 106(2):254-269.
Neurological/Behavioral
TCEP treatment resulted in behavioral effects (convulsions) and histopathological changes in the hippocampus. The seizure-related and neurohistological
effects were significantly attenuated by pretreatment with atropine or chlordizepoxide, suggesting that the hippocampal damage was related to the seizure.
In a second experiment, rats were mildly impaired in the acquisition of a reference memory task in a water maze, however, rats were consistently impaired
in performing a repeated acquisition task in the water maze.
Acute (less than or equal to 24 hr) Acute oral (gavage)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
107658
Domain
Metric
Rating
Comments
Metric 17: Consistency of Outcome Assessment High
Metric 18: Sampling Adequacy High
Metric 19: Blinding of Assessors Low
Metric 20: Negative Control Response High
Details of the outcome assessment protocol were reported and outcomes were assessed
consistently across study groups.
Reported information indicates the study used adequate sampling for the outcomes of
interest.
The study did not report whether assessors were blinded to treatment group.
The biological responses of the negative control group were adequate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Medium Although the study did not report all information to determine confounding, reported
information did not identify differences.
High There were no differences among groups for health outcomes that could influence the
outcome assessment.
High Statistical methods were adequately described.
High Data for exposure-related findings were presented for all outcomes.
Overall Quality Determination
High
Page 14 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469219 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Umezu, T„ Yonemoto, J., Soma, Y., Suzuki, T, (1998), Tris(2-chloroethyl)phosphate increases ambulatory activity in mice: pharmacological analyses of
its neurochemical mechanism. Toxicology and Applied Pharmacology 148( 1): 109-116.
Neurological/Behavioral
To examine the neurochemical (spontaneous ambulatory activity (AA)) mechanistic effect of TRCP in male mice.
Acute (less than or equal to 24 hr) Acute toxicity study
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469219
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
Test substance (tris(2-chloroethyl)phosphate) chemical name and source were identified.
Metric 2:
Test Substance Source
High
Test substance (tris(2-chloroethyl)phosphate) chemical name and source were identified.
Metric 3:
Test Substance Purity
Low
Test substance purity not reported.
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
High
Concurrent negative and vehicle control reported as olive oil or saline.
Metric 5:
Positive Controls
N/A
Not applicable for this study.
Metric 6:
Randomized Allocation of Animals
Low
No specific information on randomization or allocation of test animals was reported
other than: "All experiments in this study were performed with the approval of the Ethic
Committee for Experimental Animals of National Institute for Environmental Studies.
Mice were put individually in activity cages, and after an adaptation period of 30 min
the chemicals were administered."
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Medium
No information on preparation and storage of test material was reported.
Substance
Metric 8:
Consistency of Exposure
High
In all experiments, TRCP was administered consistently intraperitoneally; other drugs
Administration
were administered consistently subcutaneously at a constant dose volume of 0.1 ml/10 g
body weight.
Metric 9:
Reporting of Doses/Concentrations
High
TRCP was administered intraperitoneally; doses/concentrations were reported.
Metric 10:
Exposure Frequency and Duration
High
Exposure frequency and duration were reported as either a single i.p. injection of TCEP
or in combination with other chemicals.
Metric 11:
Number of Exposure Groups and
High
The number of exposure groups and dose/concentration were reported for TCEP alone
Dose/Concentration Spacing
or in combination with other chemicals.
Metric 12:
Exposure Route and Method
High
The route of administration was i.p. injection.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
High
ICR strain male mice (Clea Japan, Tokyo), 9" 12 weeks old and 35 "45 g body wt were
used in this study.
Continued on next
page...
Page 15 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469219 Table: 1 of 1
... continued from previous page
Umezu, T„ Yonemoto, J., Soma, Y., Suzuki, T, (1998), Tris(2-chloroethyl)phosphate increases ambulatory activity in mice: pharmacological analyses of
its neurochemical mechanism. Toxicology and Applied Pharmacology 148( 1): 109-116.
Neurological/Behavioral
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
To examine the neurochemical (spontaneous ambulatory activity (AA)) mechanistic effect of TRCP in male mice.
Acute (less than or equal to 24 hr) Acute toxicity study
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469219
Domain
Metric
Rating
Comments
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium Temperature and light cycle were reported; humidity was not. Each group of 10 animals
was housed in a Plexiglas-cage which had a stainless wire mesh top and wooden-flake
bedding. Commercial solid food (Clea Japan, Tokyo) and tap water were available ad
libitum. The room for breeding animals was artificially illuminated by fluorescentbulbs
on a 24-h light-dark schedule (light period: 7 a.m. "7 p.m.), andthe room temperature
was 25 6 1.0 C.
Medium Each group contained 10 animals.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High Outcome assessment methodology address or report the intended outcome(s)
of interest. The present study was conducted to clarify the acute effect of tris(2-
chloroethyl)phosphate (TRCP), an organophosphate flame retardant, on spontaneous
ambulatory activity (AA) in male ICR mice and to examine the neurochemical mecha-
nism of this effect.
High The outcome assessment was carried out consistently (i.e., using the same protocol)
across study groups (e.g., assessment at the same time after initial exposure in all study
groups.
High Sampling was adequate for the outcome assessment.
N/A Not applicable for this type of study design.
High Negative vehicle control groups were assessed.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
High No confounding variables reported.
High There were no differences among the study groups in animal attrition or health outcomes
unrelated to exposure reported.
High Mean 2-h overall AA counts were first analyzed by one-way analysis of variance
(ANOVA), followed by Scheffe"s multiple comparison test (Yoshimura and Ohashi,
1992). For time course analysis of AA after administration of TRCP, AA counts for each
10 min were plotted from the beginning to the end of the measurement. The time course
data were first examined byrepeated measures ANOVA, followed by Fisher"s PLSD
test to examine the data during the first 10 min after administration of TRCP among all
groups. Five percent was used as significance level.
High Data for all outcomes measured in this study were reported.
Overall Quality Determination
High
Page 16 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 6311010 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
FDRL, (1972). Cholinesterase studies on rats and rabbits with Olin's intermediate for Chemical 58981.
Immune/Hematological; Immune/Hematological;
Immune/Hematological: Plasma Cholinesterase levels.; Immune/Hematological: Plasma Cholinesterase levels.:
Short-term (>1-30 days) 5 days - Rat and Rabbit
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
6311010
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
All Outcomes: The test substance is explained in the document.
Metric 2:
Test Substance Source
Low
All Outcomes: Origin of test substance is "was supplied by laboratory" but no other
information.
Metric 3:
Test Substance Purity
Low
All Outcomes: There was no indication of purity or if measured, no methods were pro-
vided.
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
High
All Outcomes: Control groups had blood drawn prior to treatment to assess baseline
cholinesterase levels.
Metric 5:
Positive Controls
N/A
All Outcomes: No positive controls needed for this study.
Metric 6:
Randomized Allocation of Animals
Low
All Outcomes: No mention of randomization of animals.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Medium
All Outcomes: Information on test substance preparation indicated the test substance
Substance
was in corn oil at 10% V/V. No other information was available.
Metric 8:
Consistency of Exposure
High
All Outcomes: Exposure administration is consistent in this study.
Administration
Metric 9:
Reporting of Doses/Concentrations
High
All Outcomes: Concentrations used were reported.
Metric 10:
Exposure Frequency and Duration
High
All Outcomes: Exposure frequency and duration were reported.
Metric 11:
Number of Exposure Groups and
N/A
All Outcomes: This was not a dose-dependent study.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
All Outcomes: Exposure route was appropriate for this study.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Medium
Immune/Hematological: Test animals species and sex were reported. Strain, and other
characteristics (e.g., age, or starting body weight) were not reported but are unlikely to
have a substantial impact on results. The test animals were obtained from the laboratory
stock from the laboratory conducting the study.; Immune/Hematological: Test animals
species and sex were reported. Other characteristics (e.g., age, or starting body weight)
were not reported but are unlikely to have a substantial impact on results. The test ani-
mals were obtained from the laboratory stock from the laboratory conducting the study.
Metric 14:
Adequacy and Consistency of Animal
Low
All Outcomes: No information on animal husbandry conditions was reported.
Husbandry Conditions
Metric 15:
Number of Animals per Group
Medium
All Outcomes: The number of animals was acceptable for this type of study.
Continued on next page ...
Page 17 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 6311010 Table: 1 of 1
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
FDRL, (1972). Cholinesterase studies on rats and rabbits with Olin's intermediate for Chemical 58981.
Immune/Hematological; Immune/Hematological;
Immune/Hematological: Plasma Cholinesterase levels.; Immune/Hematological: Plasma Cholinesterase levels.:
Short-term (>1-30 days) 5 days - Rat and Rabbit
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
6311010
Domain
Metric
Rating
Comments
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Metric 19:
Metric 20:
Outcome Assessment Methodology
Consistency of Outcome Assessment
Sampling Adequacy
Blinding of Assessors
Negative Control Response
High
High
High
N/A
High
All Outcomes: The outcome methodology addressed the interests sought after in this
study.
All Outcomes: Outcome assessment was consistent in this study.
All Outcomes: Sampling in this study was adequate.
All Outcomes: Blinding not required for this study type.
All Outcomes: Negative control response was sufficient for this study.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
High All Outcomes: No confounding variables were reported.
Medium All Outcomes: Study reported mortality in some animals following treatment.
Uninformative All Outcomes: No mention of statistical analysis or if it was even performed.
Medium All Outcomes: Data were reported by day of treatment (RBC and cholinesterase levels).
Mortality in some animals was the only other information reported.
Overall Quality Determination
Uninformative
Page 18 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 790471 Table: 1 of 2
Study Citation: Hazleton Laboratories, (1983). Screening of priority chemicals for potential reproductive hazard (final report) with attachments and cover sheet.
Health Neurological/Behavioral; Neurological/Behavioral; Neurological/Behavioral; Lung/Respiratory; Skin/Connective Tissue; Nutritional/Metabolic; Mortal-
Outcome(s): ity;
Reported Health Neurological/Behavioral: Tremors, languid, prostrate, ataxia, hunched, head-tilt; Neurological/Behavioral: Tremors, languid, prostrate, ataxia, hunched,
Effect(s): head-tilt; Neurological/Behavioral; Tremors, languid, prostrate, ataxia, hunched, head-tilt; Lung/Respiratory; Wheezing, dyspnea; Skin/Connective Tissue:
Alopecia, sores, rough hair coat, piloerection; Nutritional/Metabolic; Body Weight; Mortality: Survival/Mortality;
Duration: Short-term (> 1 -30 days) 8-day Reproductive study
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 790471
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
All Outcomes: Test Substances used were listed in the introduction.
Metric 2:
Test Substance Source
High
All Outcomes: Test Substance was supplied by NIOSH.
Metric 3:
Test Substance Purity
High
All Outcomes: Each chemical purity was determined by Hazelton laboratory.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls High
Positive Controls N/A
Randomized Allocation of Animals Low
All Outcomes: Vehicle control with corn oil were used for the test substance.
All Outcomes: Positive Controls for this study were not necessary.
All Outcomes: No mention of allocation of animals in this study.
Domain 3: Exposure Characterization
Metric
7:
Metric
8:
Metric
9:
Metric
10:
Metric
11:
Metric
12:
Preparation and Storage of Test
Substance
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
Exposure Frequency and Duration
Number of Exposure Groups
Dose/Concentration Spacing
Exposure Route and Method
High All Outcomes: Preparation of test substances for experiment was adequate for study.
High All Outcomes: Exposure administration was consistent.
High All Outcomes: All doses were reported.
High All Outcomes: Exposure duration and frequency was suitable for this developmental
toxicity study.
and High All Outcomes: Dose groups and spacing was adequate for this study.
High Neurological/Behavioral: Exposure method and method was suitable for this study.;
Neurological/Behavioral: Exposure method and method was suitable for this study.;
Neurological/Behavioral: Exposure route and method was suitable for this study.; Lung/
Respiratory: Exposure route and method was suitable for this study.; Skin/Connective
Tissue: Exposure route and method was suitable for this study.; Nutritional/Metabolic:
Exposure route and method was suitable for this study.; Mortality: Exposure route and
method was suitable for this study.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics High
Metric 14: Adequacy and Consistency of Animal High
Husbandry Conditions
All Outcomes: Test animal characteristics were explained in detail.
All Outcomes: Animal husbandry conditions were reported.
Continued on next page ...
Page 19 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 790471 Table: 1 of 2
... continued from previous page
Study Citation: Hazleton Laboratories, (1983). Screening of priority chemicals for potential reproductive hazard (final report) with attachments and cover sheet.
Health Neurological/Behavioral; Neurological/Behavioral; Neurological/Behavioral; Lung/Respiratory; Skin/Connective Tissue; Nutritional/Metabolic; Mortal-
Outcome(s): ity;
Reported Health Neurological/Behavioral: Tremors, languid, prostrate, ataxia, hunched, head-tilt; Neurological/Behavioral: Tremors, languid, prostrate, ataxia, hunched,
Effect(s): head-tilt; Neurological/Behavioral; Tremors, languid, prostrate, ataxia, hunched, head-tilt; Lung/Respiratory; Wheezing, dyspnea; Skin/Connective Tissue:
Alopecia, sores, rough hair coat, piloerection; Nutritional/Metabolic; Body Weight; Mortality: Survival/Mortality;
Duration: Short-term (> 1 -30 days) 8-day Reproductive study
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 790471
Domain
Metric
Rating
Comments
Metric 15: Number of Animals per Group
Medium Neurological/Behavioral: This is a developmental study that depends on the birth of new
mice. However, there were adequate amounts of pregnant females used to do statistics.;
Neurological/Behavioral: This is a developmental study that depends on the birth of new
mice. However, there were adequate amounts of pregnant females used to do statistics.;
Neurological/Behavioral: An adequate number of animals were utilized for the MED
study.; Lung/Respiratory: An adequate number of animals were utilized for the MED
study.; Skin/Connective Tissue: An adequate number of animals were utilized for the
MED study.; Nutritional/Metabolic: An adequate number of animals were utilized for
the MED study; Mortality: An adequate number of animals were utilized for the MED
study
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Metric 19:
Metric 20:
Outcome Assessment Methodology High
Consistency of Outcome Assessment High
Sampling Adequacy High
Blinding of Assessors N/A
Negative Control Response High
All Outcomes: The assessment of outcome methodology was suitable for this study.
All Outcomes: Consistency of outcome assessment was suitable for this study.
Neurological/Behavioral: Sampling in this study was adequate for this study.; Neuro-
logical/Behavioral: Sampling in this study was adequate for this study.; Neurological/
Behavioral: Sampling in this study was adequate.; Lung/Respiratory: Sampling in this
study was adequate.; Skin/Connective Tissue: Sampling in this study was adequate.;
Nutritional/Metabolic: Sampling in this study was adequate for this study.; Mortality:
Sampling in this study was adequate for this study.
All Outcomes: Assessors did not need to be blind for this study.
Neurological/Behavioral: Negative control/vehicle response was how it should be com-
pared to the treated animals.; Neurological/Behavioral: Negative control/vehicle re-
sponse was how it should be compared to the treated animals.; Neurological/Behavioral:
Negative control/vehicle response was appropriately compared to the treated animals.;
Lung/Respiratory: Negative control/vehicle response was appropriately compared to
the treated animals.; Skin/Connective Tissue: Negative control/vehicle response was
appropriately compared to the treated animals.; Nutritional/Metabolic: Negative con-
trol/vehicle response was how it should be compared to the treated animals.; Mortality:
Negative control/vehicle response was how it should be compared to the treated animals.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
High All Outcomes: No reported differences in the variables between each animal.
High All Outcomes: No outcomes related to health exposure.
High All Outcomes: Statistical analysis was suitable for this study.
High All Outcomes: All data was reported in this study.
Continued on next page ...
Page 20 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 790471 Table: 1 of 2
... continued from previous page
Study Citation: Hazleton Laboratories, (1983). Screening of priority chemicals for potential reproductive hazard (final report) with attachments and cover sheet.
Health Neurological/Behavioral; Neurological/Behavioral; Neurological/Behavioral; Lung/Respiratory; Skin/Connective Tissue; Nutritional/Metabolic; Mortal-
Outcome(s): ity;
Reported Health Neurological/Behavioral: Tremors, languid, prostrate, ataxia, hunched, head-tilt; Neurological/Behavioral: Tremors, languid, prostrate, ataxia, hunched,
Effect(s): head-tilt; Neurological/Behavioral; Tremors, languid, prostrate, ataxia, hunched, head-tilt; Lung/Respiratory; Wheezing, dyspnea; Skin/Connective Tissue:
Alopecia, sores, rough hair coat, piloerection; Nutritional/Metabolic; Body Weight; Mortality: Survival/Mortality;
Duration: Short-term (> 1 -30 days) 8-day Reproductive study
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 790471
Domain Metric
Rating
Comments
Overall Quality Determination
High
Page 21 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 790471 Table: 2 of 2
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Hazleton Laboratories, (1983). Screening of priority chemicals for potential reproductive hazard (final report) with attachments and cover sheet.
Nutritional/Metabolic; Mortality; Lung/Respiratory;
Nutritional/Metabolic: Body Weight; Mortality: Survival/Mortality; Lung/Respiratory: Wheezing, dyspnea;
Short-term (>1-30 days) 8-day Reproductive study
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
790471
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: Test substances used were identified by established nomenclature.
High All Outcomes: Test Substance was supplied by NIOSH.
High All Outcomes: Each chemical purity was determined by Hazelton laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High All Outcomes: Vehicle control with corn oil were used for the test substance.
Metric 5: Positive Controls N/A All Outcomes: Positive Controls for this study were not necessary.
Metric 6: Randomized Allocation of Animals Low All Outcomes: No mention of allocation of animals in this study.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High All Outcomes: Preparation of test substances for experiment was adequate for study.
High All Outcomes: Exposure administration was consistent.
High All Outcomes: All doses were reported.
Low All Outcomes: There was no premating dosing and gestational dosing was on GD 7- 14.
N/A All Outcomes: There is only one exposure dose in the reproductive study.
High All Outcomes: Exposure route and method was suitable for this study.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics High All Outcomes: Test animal characteristics were explained in detail.
Metric 14: Adequacy and Consistency of Animal High All Outcomes: Animal husbandry conditions were reported.
Husbandry Conditions
Metric 15: Number of Animals per Group Medium All Outcomes: 50 pregnant mice were dosed at 940 mg/kg-d.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
Metric 17:
Consistency of Outcome Assessment
High
Metric 18:
Sampling Adequacy
High
Metric 19:
Blinding of Assessors
N/A
Metric 20:
Negative Control Response
High
All Outcomes: The assessment of outcome methodology was suitable for this study.
All Outcomes: Consistency of outcome assessment was suitable for this study.
All Outcomes: Sampling in this study was adequate.
All Outcomes: Assessors did not need to be blind for this study.
All Outcomes: Negative control/vehicle response was appropriately compared to the
treated animals.
Domain 6: Confounding / Variable Control
Continued on next page ...
Page 22 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 790471 Table: 2 of 2
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Hazleton Laboratories, (1983). Screening of priority chemicals for potential reproductive hazard (final report) with attachments and cover sheet.
Nutritional/Metabolic; Mortality; Lung/Respiratory;
Nutritional/Metabolic: Body Weight; Mortality: Survival/Mortality; Lung/Respiratory: Wheezing, dyspnea;
Short-term (>1-30 days) 8-day Reproductive study
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
790471
Domain
Metric
Rating
Comments
Metric 21:
Confounding Variables in Test Design
High
All Outcomes: No reported differences in the variables between each animal.
and Procedures
Metric 22:
Health Outcomes Unrelated to
High
All Outcomes: No outcomes related to health exposure.
Exposure
Metric 23:
Data Presentation and Analysis
High
All Outcomes: Statistical analysis was suitable for this study.
Metric 24:
Reporting of Data
High
All Outcomes: All data was reported in this study.
Overall Quality Determination High
Page 23 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 1 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High
High
High
The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was provided.
The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
The test chemical purity was 98% . The purity was both provided by the supplier and
confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High
N/A
Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were first assigned to weight groups and then, using random numbers tables,
animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
was also stable for 21 days in the dark at room temperature, or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days per week for
a total of 12 doses. Adjusted daily doses in mg/kg-day were not reported but can be
calculated using the information available. Although dose formulations were analyzed
for accuracy in the 16-week and 2-yr experiments (also reported in this reference), there
is no indication that the doses in the 16-day study were analyzed.
High Animals were gavaged 5 days per week over 16 days for a total of 12 doses. Dosing 5
days per week for a gavage study is consistent with NTP guidelines.
High The study tested 5 exposure groups plus a control. The number of groups was consistent
with NTP guidelines. The dose spacing was adequate to allow for determination of
NOAEL and LOAEL values.
Continued on next page .
Page 24 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 1 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 12:
Exposure Route and Method
High
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female F344/N rats. The test animal source (Harlan indus-
tries), age at the start of the study (7 weeks), and initial body weights were reported and
appropriate.
Medium The number of animals per cage (5/cage) was reported. Food and water were provided
ad libiutm. Animal room environments (temperature, humidity, lighting were reported.
The humidity varied considerably, ranging from 26% to 76% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is unclear
whether these deviations had any impact on the study results.
Medium The number of animals per group (5/sex) was reported and is consistent with NTP
guidelines for this study duration
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
Animals were observed for mortality daily; the outcome assessment was considered to
be sensitive and appropriate for the outcome of interest.
Metric 17:
Consistency of Outcome Assessment
High
Sufficient details of the outcome assessment protocols were provided, and outcome
assessment was carried out consistently across groups.
Metric 18:
Sampling Adequacy
High
All animals were assessed for this outcome.
Metric 19:
Blinding of Assessors
N/A
Blinding is not required. The outcome is not subjective in nature.
Metric 20:
Negative Control Response
High
No control animals died.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
High
Uninformative
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
N/A
High
The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
There were no significant body weight changes that were suggestive of palatability
issues.
No animals died. Degenerative and inflammatory lesions characteristic of infection with
sialodacryoadenitis virus (SDA) were observed in the salivary glands and lungs of most
dosed and control rats. Because all groups appeared to be affected and it is unknown
how this infection may have impacted the study results, this study is considered to be
unacceptable.
Statistical analysis was not necessary. No animals died in the study.
Animal survival was quantitatively reported by sex and exposure group. No animals died
in the study.
Continued on next page .
Page 25 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 1 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric
Rating
Comments
Overall Quality Determination
Uninformative
Page 26 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 2 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High
High
High
The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was provided.
The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
The test chemical purity was 98% . The purity was both provided by the supplier and
confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High
N/A
Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were first assigned to weight groups and then, using random numbers tables,
animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
was also stable for 21 days in the dark at room temperature, or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days per week for
a total of 12 doses. Adjusted daily doses in mg/kg-day were not reported but can be
calculated using the information available. Although dose formulations were analyzed
for accuracy in the 16-week and 2-yr experiments (also reported in this reference), there
is no indication that the doses in the 16-day study were analyzed.
High Animals were gavaged 5 days per week over 16 days for a total of 12 doses. Dosing 5
days per week for a gavage study is consistent with NTP guidelines.
High The study tested 5 exposure groups plus a control. The number of groups was consistent
with NTP guidelines. The dose spacing was adequate to allow for determination of
NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Continued on next page .
Page 27 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 2 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High
Medium
Medium
The study used male and female F344/N rats. The test animal source (Harlan indus-
tries), age at the start of the study (7 weeks), and initial body weights were reported and
appropriate.
The number of animals per cage (5/cage) was reported. Food and water were provided
ad libiutm. Animal room environments (temperature, humidity, lighting were reported.
The humidity varied considerably, ranging from 26% to 76% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is unclear
whether these deviations had any impact on the study results.
The number of animals per group (5/sex) was reported and is consistent with NTP
guidelines for this study duration
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology High Body weights were recorded initially, weekly, and at termination. This is consistent with
NTP guidelines and the methods are sensitive and appropriate to assess this outcome of
interest.
Metric
17:
Consistency of Outcome Assessment
High
Sufficient details of the outcome assessment protocols were provided, and outcome
assessment was carried out consistently across groups.
Metric
18:
Sampling Adequacy
High
Measurements were collected from all of the treated animals. Sampling was sufficient
for statistical analysis.
Metric
19:
Blinding of Assessors
N/A
Blinding is not required. The outcome is not subjective in nature.
Metric
20:
Negative Control Response
High
The negative control responses were reported and and appropriate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design High The study did not measure food or water intake, but this was not a dietary or drinking
and Procedures water study, and these endpoints are not required for this study type according to NTP.
There were no significant body weight changes that were suggestive of palatability
issues.
Metric 22: Health Outcomes Unrelated to Uninformative No animals died. Degenerative and inflammatory lesions characteristic of infection with
Exposure sialodacryoadenitis virus (SDA) were observed in the salivary glands and lungs of most
dosed and control rats. Because all groups appeared to be affected and it is unknown
how this infection may have impacted the study results, this study is considered to be
unacceptable.
Metric 23: Data Presentation and Analysis High Statistical methods were adequately described and were appropriate for the dataset.
Statistical significance was shown where appropriate.
Continued on next page ...
Page 28 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 2 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric
Rating
Comments
Metric 24: Reporting of Data
High
Body weight data were reported quantitatively for both sexes and all dose groups. Data
were presented as means ± SE.
Overall Quality Determination
Uninformative
Page 29 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 3 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was provided.
Metric 2: Test Substance Source High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
Metric 3: Test Substance Purity High The test chemical purity was 98% . The purity was both provided by the supplier and
confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
N/A Positive controls are not required for this study type.
Medium Animals were first assigned to weight groups and then, using random numbers tables,
animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
was also stable for 21 days in the dark at room temperature, or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium The doses were clearly reported. Animals were exposed to 0, 44, 88, 175, 350, or 700
mg/kg-day, 5 days per week. Time-adjusted doses were not reported but can be deter-
mined using the information available. Although dose formulations were analyzed for
accuracy in the 16-week and 2-yr experiments (also reported in this reference), there is
no indication that the doses in the 16-day study were analyzed.
High Animals were gavaged 5 days per week over 16 days for a total of 12 doses. Dosing 5
days per week for a gavage study is consistent with NTP guidelines.
High The study tested 5 exposure groups plus a control. The number of groups was consistent
with NTP guidelines. The dose spacing was adequate to allow for determination of
NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Continued on next page ...
Page 30 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 3 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9 weeks old), and initial body weights were reported
and appropriate.
Medium The number of animals per cage (5/cage) was reported. The NTP guideline specifies that
male mice should be housed individually for all studies. Food and water were provided
ad libitum. Animal room environments (temperature, humidity, lighting) were reported.
The humidity range was large (26% to 76% ). This deviates from NTP guidelines which
state humidity should not be below 35% or above 65% . It is unclear whether these
deviations had a significant impact on the study results.
Medium The number of animals per group (5/sex) was reported and is consistent with NTP
guidelines for this study duration.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
Animals were observed for mortality daily; the outcome assessment was considered to
be sensitive and appropriate for the outcome of interest.
Metric 17:
Consistency of Outcome Assessment
High
Sufficient details of the outcome assessment protocols were provided, and outcome
assessment was carried out consistently across groups.
Metric 18:
Sampling Adequacy
High
All animals were assessed for this outcome.
Metric 19:
Blinding of Assessors
N/A
Blinding is not required. The outcome is not subjective in nature.
Metric 20:
Negative Control Response
High
No control animals died.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
Metric 22:
Health Outcomes Unrelated to
Exposure
Low The initial body weights of female-treated mice were all significantly higher (by 12%
- 20% ) than the body weights of controls. This is confusing because animals had been
distributed into weight classes and then assigned to cages using random numbers tables.
It is unclear how the initial body weights of treated animals vs. controls were different
to the degree observed. The study authors did not comment on this. The study did not
measure food or water intake, but this was not a dietary or drinking water study, and
these endpoints are not required for this study type according to NTP. However, the
treated animals gained significantly less body weight over the course of the study than
the controls. It is unknown if this was related to the fact that their initial body weights
were higher, or if there indeed had been decreases in food or water intake.
Medium There were three deaths attributed to gavage trauma. One male each at 175 and 350 mg/
kg, and one female at 700 mg/kg. Other than reducing the sample size, these deaths are
not expected to have a significant impact on the study results. No other health outcomes
unrelated to exposure were reported.
Continued on next page ...
Page 31 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 3 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
N/A Statistical analysis was not necessary. No animal deaths were attributed to TCEP expo-
sure.
High Mortality data were reported quantitatively. The cause and day of death were specified.
Overall Quality Determination
High
Page 32 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 4 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was provided.
Metric 2: Test Substance Source High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
Metric 3: Test Substance Purity High The test chemical purity was 98% . The purity was both provided by the supplier and
confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
N/A Positive controls are not required for this study type.
Medium Animals were first assigned to weight groups and then, using random numbers tables,
animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
was also stable for 21 days in the dark at room temperature, or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium The doses were clearly reported. Animals were exposed to 0, 44, 88, 175, 350, or 700
mg/kg-day, 5 days per week. Time-adjusted doses were not reported but can be deter-
mined using the information available. Although dose formulations were analyzed for
accuracy in the 16-week and 2-yr experiments (also reported in this reference), there is
no indication that the doses in the 16-day study were analyzed.
High Animals were gavaged 5 days per week over 16 days for a total of 12 doses. Dosing 5
days per week for a gavage study is consistent with NTP guidelines.
High The study tested 5 exposure groups plus a control. The number of groups was consistent
with NTP guidelines. The dose spacing was adequate to allow for determination of
NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Continued on next page ...
Page 33 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 4 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9 weeks old), and initial body weights were reported
and appropriate.
Medium The number of animals per cage (5/cage) was reported. The NTP guideline specifies that
male mice should be housed individually for all studies. Food and water were provided
ad libiutm. Animal room environments (temperature, humidity, lighting were reported.
The humidity range was large (26% to 76% ). This deviates from NTP guidelines which
state humidity should not be below 35% or above 65% . It is unclear whether these
deviations had a significant impact on the study results.
Medium The number of animals per group (5/sex) was reported and is consistent with NTP
guidelines for this study duration
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High Body weights were recorded initially, weekly, and at termination. This is consistent
with NTP guidelines and the methods are sensitive and appropriate for the outcome of
interest.
High Sufficient details of the outcome assessment protocols were provided, and outcome
assessment was carried out consistently across groups.
High Measurements were collected from all of the treated animals. Due to deaths, necropsy
body weights were measured in 4/5 animals in the 175 and 300 mg/kg-day groups
(males), and in the 700 mg/kg-day group (females). Sampling was sufficient for sta-
tistical analysis.
N/A Blinding is not required. The outcome is not subjective in nature.
Medium The negative control males lost a small amount of weight ( 3% ) during the 16 days of
the study. Control females gained weight (19% ) which is a more expected response.
The study authors did not discuss these observations. It is unclear whether the response
in control males had an impact on the study results. It did not result in any significant
differences in final body weights.
Domain 6: Confounding / Variable Control
Continued on next page .
Page 34 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 4 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 21:
Confounding Variables in Test Design
and Procedures
Low
The initial body weights of female-treated mice were all significantly higher (by 12%
- 20% ) than the body weights of controls. This is confusing because animals had been
distributed into weight classes and then assigned to cages using random numbers tables.
It is unclear how the initial body weights of treated animals vs. controls were different
to the degree observed. The study authors did not comment on this. The study did not
measure food or water intake, but this was not a dietary or drinking water study, and
these endpoints are not required for this study type according to NTP. However, the
treated animals gained significantly less body weight over the course of the study than
the controls. It is unknown if this was related to the fact that their initial body weights
were higher, or if there indeed had been decreases in food or water intake.
Metric 22:
Health Outcomes Unrelated to
Medium
There were three deaths attributed to gavage trauma. One male each at 175 and 350 mg/
Exposure
kg, and one female at 700 mg/kg. Other than reducing the sample size, these deaths are
not expected to have a significant impact on the study results. No other health outcomes
unrelated to exposure were reported.
Metric 23:
Data Presentation and Analysis
High
Statistical methods were adequately described and were appropriate for the dataset.
Statistical significance was shown where appropriate.
Metric 24:
Reporting of Data
High
Body weight data were reported quantitatively for both sexes and all dose groups. Data
were presented as means ± SE.
Overall Quality Determination
High
Page 35 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 5 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Gastrointestinal; Musculoskeletal; Thyroid; Ocular/Sensory; Endocrine; Skin/Connective Tissue;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum),
salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal
muscle, bone); Thyroid: Gross necropsy and histopathology (thyroid); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Endocrine:
Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid); Skin/Connective Tissue: Gross necropsy, histopathology
(skin);
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High
High
High
All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was provided.
All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
All Outcomes: The test chemical purity was 98% . The purity was both provided by
the supplier and confirmed via analysis (NMR and elemental analysis) by the study
laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High
N/A
Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were first assigned to weight groups and then, using random
numbers tables, animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test
Substance
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High
High
Medium
High
All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) was also stable for 21 days in the dark at room temperature, or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks.
All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
All Outcomes: Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days
per week for a total of 12 doses. Adjusted daily doses in mg/kg-day were not reported
but can be calculated using the information available. Although dose formulations were
analyzed for accuracy in the 16-week and 2-yr experiments (also reported in this refer-
ence), there is no indication that the doses in the 16-day study were analyzed.
All Outcomes: Animals were gavaged 5 days per week over 16 days for a total of 12
doses. Dosing 5 days per week for a gavage study is consistent with NTP guidelines.
Continued on next page .
Page 36 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 5 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Gastrointestinal; Musculoskeletal; Thyroid; Ocular/Sensory; Endocrine; Skin/Connective Tissue;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum),
salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal
muscle, bone); Thyroid: Gross necropsy and histopathology (thyroid); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Endocrine:
Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid); Skin/Connective Tissue: Gross necropsy, histopathology
(skin);
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
High
All Outcomes: The study tested 5 exposure groups plus a control. The number of groups
was consistent with NTP guidelines. The dose spacing was adequate to allow for deter-
mination of NOAEL and LOAEL values.
Metric 12:
Exposure Route and Method
High
All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High All Outcomes: The study used male and female F344/N rats. The test animal source
(Harlan industries), age at the start of the study (7 weeks), and initial body weights were
reported and appropriate.
Medium All Outcomes: The number of animals per cage (5/cage) was reported. Food and water
were provided ad libiutm. Animal room environments (temperature, humidity, lighting
were reported. The humidity varied considerably, ranging from 26% to 76% . This devi-
ates from NTP guidelines which state humidity should not be below 35% or above 65% .
It is unclear whether these deviations had any impact on the study results.
Medium All Outcomes: The number of animals per group (5/sex) was reported and is consistent
with NTP guidelines for this study duration
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
High All Outcomes: Histopathological analysis was conducted on tissue(s) from this organ/
system and histopathology is considered to be a sensitive and appropriate method to
assess this outcome of interest and is consistent with the NTP guidelines for this study
type
High All Outcomes: Sufficient details of the outcome assessment protocols (organ weights
and histopathology) were provided, and outcome assessment was carried out consis-
tently across groups. Blood for measurement of cholinesterase activity was collected
from all animals at terminal sacrifice.
Medium All Outcomes: Histopathology was conducted on controls and high-dose animals only,
and no effects were observed at the high dose. The methods report that all animals were
examined, but since negative findings were qualitatively reported, the sample size cannot
be verified.
N/A All Outcomes: Blinding is not required for initial histopathology.
Continued on next page .
Page 37 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 5 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Gastrointestinal; Musculoskeletal; Thyroid; Ocular/Sensory; Endocrine; Skin/Connective Tissue;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum),
salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal
muscle, bone); Thyroid: Gross necropsy and histopathology (thyroid); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Endocrine:
Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid); Skin/Connective Tissue: Gross necropsy, histopathology
(skin);
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 20:
Negative Control Response
Low
All Outcomes: The appropriateness of the negative control response for histopathology
cannot be determined because incidence data were not provided. The study authors did
not describe any concerns about a high background in controls.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
High
All Outcomes: The study did not measure food or water intake, but these but this was
not a dietary or drinking water study, and these endpoints are not required for this study
type according to NTP. There were no significant body weight changes that were sug-
gestive of palatability issues.
Metric 22:
Health Outcomes Unrelated to
Uninformative
All Outcomes: No animals died. Degenerative and inflammatory lesions characteristic
Exposure
of infection with sialodacryoadenitis virus (SDA) were observed in the salivary glands
and lungs of most dosed and control rats. Because all groups appeared to be affected
and it is unknown how this infection may have impacted the study results, this study is
considered to be unacceptable.
Metric 23:
Data Presentation and Analysis
High
All Outcomes: Statistical methods were adequately described and were appropriate for
the dataset. Statistical significance was shown where appropriate.
Metric 24:
Reporting of Data
High
All Outcomes: Negative gross necropsy and histopathological findings were reported
qualitatively in the text. The study reported that no gross observations or histopatho-
logical lesions attributable to exposure were observed. This statement applied to both
mice and rats. No organ-specific results were reported, and no quantitative data were
provided.
Overall Quality Determination
Uninformative
Page 38 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 6 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Gastrointestinal; Musculoskeletal; Thyroid; Skin/Connective Tissue; Ocular/Sensory; Endocrine;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum),
salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal
muscle, bone); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Ocular/Sensory:
Gross necropsy, histopathology (harderian gland); Endocrine: Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% . The purity was both provided by
the supplier and confirmed via analysis (NMR and elemental analysis) by the study
laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
N/A All Outcomes: Positive controls are not required for this study type.
Medium All Outcomes: Animals were first assigned to weight groups and then, using random
numbers tables, animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) was also stable for 21 days in the dark at room temperature, or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks.
High All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
Medium All Outcomes: The doses were clearly reported. Animals were exposed to 0, 44, 88,
175, 350, or 700 mg/kg-day, 5 days per week. Time-adjusted doses were not reported
but can be determined using the information available. Although dose formulations
were analyzed for accuracy in the 16-week and 2-yr experiments (also reported in this
reference), there is no indication that the doses in the 16-day study were analyzed.
High All Outcomes: Animals were gavaged 5 days per week over 16 days for a total of 12
doses. Dosing 5 days per week for a gavage study is consistent with NTP guidelines.
Continued on next page ...
Page 39 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 6 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Gastrointestinal; Musculoskeletal; Thyroid; Skin/Connective Tissue; Ocular/Sensory; Endocrine;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum),
salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal
muscle, bone); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Ocular/Sensory:
Gross necropsy, histopathology (harderian gland); Endocrine: Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11: Number of Exposure Groups
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
and High All Outcomes: The study tested 5 exposure groups plus a control. The number of groups
was consistent with NTP guidelines. The dose spacing was adequate to allow for deter-
mination of NOAEL and LOAEL values.
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High All Outcomes: The study used male and female B6C3F1 mice. The test animal source
(Harlan industries), age at the start of the study (9 weeks old), and initial body weights
were reported and appropriate.
Medium All Outcomes: The number of animals per cage (5/cage) was reported. The NTP guide-
line specifies that male mice should be housed individually for all studies. Food and
water were provided ad libiutm. Animal room environments (temperature, humidity,
lighting were reported. The humidity range was large (26% to 76% ). This deviates from
NTP guidelines which state humidity should not be below 35% or above 65% . It is
unclear whether these deviations had a significant impact on the study results.
Medium All Outcomes: The number of animals per group (5/sex) was reported and is consistent
with NTP guidelines for this study duration
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Metric 19:
Metric 20:
Outcome Assessment Methodology High
Consistency of Outcome Assessment High
Sampling Adequacy Medium
Blinding of Assessors N/A
Negative Control Response Low
All Outcomes: Histopathological analysis was conducted on tissue(s) from this organ/
system and histopathology is considered to be a sensitive and appropriate method for
this outcome of interest. The methods were consistent with the NTP guidelines for this
study type.
All Outcomes: Sufficient details of the outcome assessment protocols were provided,
and outcome assessment was carried out consistently across groups.
All Outcomes: Histopathology was conducted on controls and high-dose animals only,
but no effects were observed at the high dose. The methods suggest that all animals were
examined, but since negative findings were qualitatively reported, the sample size cannot
be verified.
All Outcomes: Blinding is not required. The outcome is either not subjective in nature
(organ weights), or blinding is not required (initial histopathology).
All Outcomes: The appropriateness of the negative control response for histopathology
cannot be determined because the biological responses of the controls were not reported.
Continued on next page ...
Page 40 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 6 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Gastrointestinal; Musculoskeletal; Thyroid; Skin/Connective Tissue; Ocular/Sensory; Endocrine;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum),
salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal
muscle, bone); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Ocular/Sensory:
Gross necropsy, histopathology (harderian gland); Endocrine: Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Low All Outcomes: The initial body weights of female-treated mice were all significantly
higher (by 12% - 20% ) than the body weights of controls. This is confusing because an-
imals had been distributed into weight classes and then assigned to cages using random
numbers tables. It is unclear how the initial body weights of treated animals vs. controls
were different to the degree observed. The study authors did not comment on this. The
study did not measure food or water intake, but this was not a dietary or drinking water
study, and these endpoints are not required for this study type according to NTP. How-
ever, the treated animals gained significantly less body weight over the course of the
study than the controls. It is unknown if this was related to the fact that their initial body
weights were higher, or if there indeed had been decreases in food or water intake.
Medium All Outcomes: There were three deaths attributed to gavage trauma. One male each at
175 and 350 mg/kg, and one female at 700 mg/kg. Other than reducing the sample size,
these deaths are not expected to have a significant impact on the study results. No other
health outcomes unrelated to exposure were reported.
High All Outcomes: Statistical methods were adequately described and were appropriate for
the dataset. Statistical significance was shown where appropriate.
Continued on next page ...
Page 41 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 6 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Gastrointestinal; Musculoskeletal; Thyroid; Skin/Connective Tissue; Ocular/Sensory; Endocrine;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum),
salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal
muscle, bone); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Ocular/Sensory:
Gross necropsy, histopathology (harderian gland); Endocrine: Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 24: Reporting of Data
High Reproductive/Developmental: Negative gross necropsy and histopathological findings
were reported qualitatively in the text. The study reported that no gross observations
or histopathological lesions attributable to exposure were observed. This statement ap-
plied to both mice and rats. No organ-specific results were reported.; Gastrointestinal:
Negative gross necropsy and histopathological findings were reported qualitatively in
the text. The study reported that no gross observations or histopathological lesions at-
tributable to exposure were observed. This statement applied to both mice and rats. No
organ-specific results were reported.; Musculoskeletal: Negative gross necropsy and
histopathological findings were reported qualitatively in the text. The study reported
that no gross observations or histopathological lesions attributable to exposure were
observed. No organ-specific results were reported.; Thyroid: Negative gross necropsy
and histopathological findings were reported qualitatively in the text. The study reported
that no gross observations or histopathological lesions attributable to exposure were ob-
served. This statement applied to both mice and rats. No organ-specific results were re-
ported.; Skin/Connective Tissue: Negative gross necropsy and histopathological findings
were reported qualitatively in the text. The study reported that no gross observations or
histopathological lesions attributable to exposure were observed. This statement applied
to both mice and rats. No organ-specific results were reported.; Ocular/Sensory: Nega-
tive gross necropsy and histopathological findings were reported qualitatively in the text.
The study reported that no gross observations or histopathological lesions attributable to
exposure were observed. This statement applied to both mice and rats. No organ-specific
results were reported.; Endocrine: Negative gross necropsy and histopathological find-
ings were reported qualitatively in the text. The study reported that no gross observa-
tions or histopathological lesions attributable to exposure were observed. This statement
applied to both mice and rats. No organ-specific results were reported.
Overall Quality Determination
High
Page 42 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Neurological/Behavioral; Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Neurological/Behavioral: Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain
weights, gross necropsy, histopathology (brain); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Hepatic/Liver: Liver weights,
gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol
dehydrogenase, cholesterol); Renal/Kidney; Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/
Respiratory: Gross necropsy, histopathology (lung, nose, trachea); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes
with differential, MCV, MCH, MCHC, and reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular
and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High
High
High
All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was provided.
All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
All Outcomes: The test chemical purity was 98% . The purity was both provided by
the supplier and confirmed via analysis (NMR and elemental analysis) by the study
laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High
N/A
Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were first assigned to weight groups and then, using random
numbers tables, animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test
Substance
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
High
High
Medium
All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) was also stable for 21 days in the dark at room temperature, or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks.
All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
All Outcomes: Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days
per week for a total of 12 doses. Adjusted daily doses in mg/kg-day were not reported
but can be calculated using the information available. Although dose formulations were
analyzed for accuracy in the 16-week and 2-yr experiments (also reported in this refer-
ence), there is no indication that the doses in the 16-day study were analyzed.
Continued on next page .
Page 43 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Neurological/Behavioral; Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Neurological/Behavioral: Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain
weights, gross necropsy, histopathology (brain); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Hepatic/Liver: Liver weights,
gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol
dehydrogenase, cholesterol); Renal/Kidney; Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/
Respiratory: Gross necropsy, histopathology (lung, nose, trachea); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes
with differential, MCV, MCH, MCHC, and reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular
and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10:
Exposure Frequency and Duration
High
All Outcomes: Animals were gavaged 5 days per week over 16 days for a total of 12
doses. Dosing 5 days per week for a gavage study is consistent with NTP guidelines.
Metric 11:
Number of Exposure Groups and
High
All Outcomes: The study tested 5 exposure groups plus a control. The number of groups
Dose/Concentration Spacing
was consistent with NTP guidelines. The dose spacing was adequate to allow for deter-
mination of NOAEL and LOAEL values.
Metric 12:
Exposure Route and Method
High
All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
High
All Outcomes: The study used male and female F344/N rats. The test animal source
(Harlan industries), age at the start of the study (7 weeks), and initial body weights were
reported and appropriate.
Metric 14:
Adequacy and Consistency of Animal
Medium
All Outcomes: The number of animals per cage (5/cage) was reported. Food and water
Husbandry Conditions
were provided ad libiutm. Animal room environments (temperature, humidity, lighting
were reported. The humidity varied considerably, ranging from 26% to 76% . This devi-
ates from NTP guidelines which state humidity should not be below 35% or above 65% .
It is unclear whether these deviations had any impact on the study results.
Metric 15:
Number of Animals per Group
Medium
All Outcomes: The number of animals per group (5/sex) was reported and is consistent
with NTP guidelines for this study duration
Domain 5: Outcome Assessment
Continued on next page .
Page 44 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Neurological/Behavioral; Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Neurological/Behavioral: Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain
weights, gross necropsy, histopathology (brain); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Hepatic/Liver: Liver weights,
gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol
dehydrogenase, cholesterol); Renal/Kidney; Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/
Respiratory: Gross necropsy, histopathology (lung, nose, trachea); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes
with differential, MCV, MCH, MCHC, and reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular
and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 16: Outcome Assessment Methodology
High
Metric 17: Consistency of Outcome Assessment
High
Neurological/Behavioral: Serum Cholinesterase activity was determined at study ter-
mination. Absolute and relative organ weights were measured, and all animals were
subjected to gross necropsy. Brain tissue was examined histologically (other neuronal
tissues were not examined). The outcome assessment methodologies were described in
sufficient detail and were sensitive to the outcome of interest.; Cardiovascular: Absolute
and relative organ weights were recorded and histopathological analysis was conducted
on tissue(s) from this organ/system. The outcome assessment methods were sensitive
and appropriate for this outcome of interest and were consistent with NTP guidelines.;
Hepatic/Liver: Absolute and relative organ weights were recorded and histopathological
analysis was conducted on tissue(s) from this organ/system. The outcome assessment
methods were sensitive and appropriate for this outcome of interest and were consistent
with NTP guidelines.; Renal/Kidney: Absolute and relative organ weights were recorded
and histopathological analysis was conducted on tissue(s) from this organ/system. The
outcome assessment methods were sensitive and appropriate for this outcome of inter-
est and were consistent with NTP guidelines.; Lung/Respiratory: Absolute and relative
organ weights were recorded and histopathological analysis was conducted on tissue(s)
from this organ/system. The outcome assessment methods were sensitive and appro-
priate for this outcome of interest and were consistent with NTP guidelines.; Immune/
Hematological: Absolute and relative organ weights were recorded and histopatho-
logical analysis was conducted on tissue(s) from this organ/system. The outcome as-
sessment methods were sensitive and appropriate for this outcome of interest and were
consistent with NTP guidelines.
All Outcomes: Sufficient details of the outcome assessment protocols (organ weights
and histopathology) were provided, and outcome assessment was carried out consis-
tently across groups. Blood for measurement of cholinesterase activity was collected
from all animals at terminal sacrifice.
Continued on next page ...
Page 45 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Neurological/Behavioral; Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Neurological/Behavioral: Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain
weights, gross necropsy, histopathology (brain); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Hepatic/Liver: Liver weights,
gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol
dehydrogenase, cholesterol); Renal/Kidney; Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/
Respiratory: Gross necropsy, histopathology (lung, nose, trachea); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes
with differential, MCV, MCH, MCHC, and reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular
and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 18: Sampling Adequacy
Medium
Metric 19: Blinding of Assessors
N/A
Neurological/Behavioral: Organ weights were measured from 5/5 animals from all
groups, except for the 88 mg/kg-day group (4/5). Histopathology was conducted on
controls and high-dose animals only, but no effects were observed at the high dose.; Car-
diovascular: Organ weights were measured from 5/5 animals for all groups except 88
mg/kg-day males (4/5). Histopathology was conducted on controls and high-dose ani-
mals only, and no effects were observed at the high dose. The methods suggest that all
animals were examined, but since negative findings were qualitatively reported, the sam-
ple size for this endpoint cannot be verified.; Hepatic/Liver: Organ weights were mea-
sured from 5/5 animals for all groups except 88 mg/kg-day males (4/5). Histopathology
was conducted on controls and high-dose animals only, and no effects were observed
at the high dose. The methods suggest that all animals were examined, but since neg-
ative findings were qualitatively reported, the sample size for this endpoint cannot be
verified.; Renal/Kidney: Organ weights were measured from 5/5 animals for all groups
except 88 mg/kg-day males (4/5). Histopathology was conducted on controls and high-
dose animals only, and no effects were observed at the high dose. The methods sug-
gest that all animals were examined, but since negative findings were qualitatively re-
ported, the sample size for this endpoint cannot be verified.; Lung/Respiratory: Organ
weights were measured from 5/5 animals for all groups except 88 mg/kg-day males
(4/5). Histopathology was conducted on controls and high-dose animals only, and no
effects were observed at the high dose. The methods suggest that all animals were ex-
amined, but since negative findings were qualitatively reported, the sample size for this
endpoint cannot be verified.; Immune/Hematological: Organ weights were measured
from 5/5 animals for all groups except 88 mg/kg-day males (4/5). Histopathology was
conducted on controls and high-dose animals only, and no effects were observed at the
high dose. The methods suggest that all animals were examined, but since negative find-
ings were qualitatively reported, the sample size for this endpoint cannot be verified.
Neurological/Behavioral: Blinding is not required. The outcome is either not subjective
in nature (organ weights), or blinding is not required (initial histopathology).; Cardio-
vascular: Blinding is not required for initial histopathology.; Hepatic/Liver: Blinding is
not required for initial histopathology.; Renal/Kidney: Blinding is not required for initial
histopathology.; Lung/Respiratory: Blinding is not required for initial histopathology.;
Immune/Hematological: Blinding is not required for initial histopathology.
Continued on next page .
Page 46 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Neurological/Behavioral; Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Neurological/Behavioral: Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain
weights, gross necropsy, histopathology (brain); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Hepatic/Liver: Liver weights,
gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol
dehydrogenase, cholesterol); Renal/Kidney; Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/
Respiratory: Gross necropsy, histopathology (lung, nose, trachea); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes
with differential, MCV, MCH, MCHC, and reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular
and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 20: Negative Control Response
Medium Neurological/Behavioral: The appropriateness of the negative control response for
histopathology cannot be determined because incidence data were not provided. The
study authors did not describe any concerns about a high background in controls. The
control responses for organ weights and cholinesterase activity were appropriate.; Car-
diovascular: The appropriateness of the negative control responses for histopathology
cannot be determined because incidence data were not provided. The study authors did
not describe any concerns about high background in controls. Organ weight data for
controls appeared to be appropriate.; Hepatic/Liver: The appropriateness of the nega-
tive control responses for histopathology cannot be determined because incidence data
were not provided. The study authors did not describe any concerns about high back-
ground in controls. Organ weight data for controls appeared to be appropriate.; Renal/
Kidney: The appropriateness of the negative control responses for histopathology can-
not be determined because incidence data were not provided. The study authors did
not describe any concerns about high background in controls. Organ weight data for
controls appeared to be appropriate.; Lung/Respiratory: The appropriateness of the neg-
ative control responses for histopathology cannot be determined because incidence data
were not provided. The study authors did not describe any concerns about high back-
ground in controls. Organ weight data for controls appeared to be appropriate.; Immune/
Hematological: The appropriateness of the negative control responses for histopathol-
ogy cannot be determined because incidence data were not provided. The study authors
did not describe any concerns about high background in controls. Organ weight data for
controls appeared to be appropriate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
High All Outcomes: The study did not measure food or water intake, but these but this was
not a dietary or drinking water study, and these endpoints are not required for this study
type according to NTP. There were no significant body weight changes that were sug-
gestive of palatability issues.
Uninformative All Outcomes: No animals died. Degenerative and inflammatory lesions characteristic
of infection with sialodacryoadenitis virus (SDA) were observed in the salivary glands
and lungs of most dosed and control rats. Because all groups appeared to be affected
and it is unknown how this infection may have impacted the study results, this study is
considered to be unacceptable.
Continued on next page .
Page 47 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Neurological/Behavioral; Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Neurological/Behavioral: Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain
weights, gross necropsy, histopathology (brain); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Hepatic/Liver: Liver weights,
gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol
dehydrogenase, cholesterol); Renal/Kidney; Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/
Respiratory: Gross necropsy, histopathology (lung, nose, trachea); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes
with differential, MCV, MCH, MCHC, and reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular
and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
High
High
All Outcomes: Statistical methods were adequately described and were appropriate for
the dataset. Statistical significance was shown where appropriate.
Neurological/Behavioral: Brain weight and serum cholinesterase data were reported
quantitatively for both sexes and all dose groups. Data were presented as means ± SE.
Negative gross necropsy and histopathological findings were reported qualitatively in
the text. The study reported that no gross observations or histopathological lesions at-
tributable to exposure were observed. This statement applied to both mice and rats;
no organ-specific results were reported, and no quantitative data were provided.; Car-
diovascular: Organ weight data were reported quantitatively. Data were presented as
means ± SE. Negative gross necropsy and histopathological findings were reported
qualitatively in the text. The study reported that no gross observations or histopatho-
logical lesions attributable to exposure were observed. This statement applied to both
mice and rats.; Hepatic/Liver: Organ weight data were reported quantitatively. Data
were presented as means ± SE. Negative gross necropsy and histopathological findings
were reported qualitatively in the text. The study reported that no gross observations or
histopathological lesions attributable to exposure were observed. This statement applied
to both mice and rats.; Renal/Kidney: Organ weight data were reported quantitatively.
Data were presented as means ± SE. Negative gross necropsy and histopathological
findings were reported qualitatively in the text. The study reported that no gross ob-
servations or histopathological lesions attributable to exposure were observed. This
statement applied to both mice and rats.; Lung/Respiratory: Organ weight data were
reported quantitatively. Data were presented as means ± SE. Negative gross necropsy
and histopathological findings were reported qualitatively in the text. The study reported
that no gross observations or histopathological lesions attributable to exposure were ob-
served. This statement applied to both mice and rats.; Immune/Hematological: Organ
weight data were reported quantitatively. Data were presented as means ± SE. Negative
gross necropsy and histopathological findings were reported qualitatively in the text.
The study reported that no gross observations or histopathological lesions attributable to
exposure were observed. This statement applied to both mice and rats.
Overall Quality Determination
Uninformative
Page 48 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Cardiovascular; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspar-
tate aminotransferase, sorbitol dehydrogenase, cholesterol); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Renal/Kidney:
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/Respiratory; Gross necropsy, histopathology
(lung, nose, trachea); Immune/Hematological; Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1; Test Substance Identity
Metric 2; Test Substance Source
Metric 3; Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% . The purity was both provided by
the supplier and confirmed via analysis (NMR and elemental analysis) by the study
laboratory.
Domain 2; Test Design
Metric 4; Negative and Vehicle Controls
Metric 5; Positive Controls
Metric 6; Randomized Allocation of Animals
High All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
N/A All Outcomes: Positive controls are not required for this study type.
Medium All Outcomes: Animals were first assigned to weight groups and then, using random
numbers tables, animals were were assigned to cages and then to groups.
Domain 3; Exposure Characterization
Metric 7; Preparation and Storage of Test
Substance
Metric 8; Consistency of Exposure
Administration
Metric 9; Reporting of Doses/Concentrations
Metric 10; Exposure Frequency and Duration
High All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) was also stable for 21 days in the dark at room temperature, or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks.
High All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
Medium All Outcomes: The doses were clearly reported. Animals were exposed to 0, 44, 88,
175, 350, or 700 mg/kg-day, 5 days per week. Time-adjusted doses were not reported
but can be determined using the information available. Although dose formulations
were analyzed for accuracy in the 16-week and 2-yr experiments (also reported in this
reference), there is no indication that the doses in the 16-day study were analyzed.
High All Outcomes: Animals were gavaged 5 days per week over 16 days for a total of 12
doses. Dosing 5 days per week for a gavage study is consistent with NTP guidelines.
Continued on next page ...
Page 49 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Cardiovascular; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspar-
tate aminotransferase, sorbitol dehydrogenase, cholesterol); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Renal/Kidney:
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/Respiratory; Gross necropsy, histopathology
(lung, nose, trachea); Immune/Hematological; Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11: Number of Exposure Groups
Dose/Concentration Spacing
Metric 12; Exposure Route and Method
and High All Outcomes: The study tested 5 exposure groups plus a control. The number of groups
was consistent with NTP guidelines. The dose spacing was adequate to allow for deter-
mination of NOAEL and LOAEL values.
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4; Test Animals
Metric 13; Test Animal Characteristics
Metric 14; Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15; Number of Animals per Group
High All Outcomes: The study used male and female B6C3F1 mice. The test animal source
(Harlan industries), age at the start of the study (9 weeks old), and initial body weights
were reported and appropriate.
Medium All Outcomes: The number of animals per cage (5/cage) was reported. The NTP guide-
line specifies that male mice should be housed individually for all studies. Food and
water were provided ad libiutm. Animal room environments (temperature, humidity,
lighting were reported. The humidity range was large (26% to 76% ). This deviates from
NTP guidelines which state humidity should not be below 35% or above 65% . It is
unclear whether these deviations had a significant impact on the study results.
Medium All Outcomes: The number of animals per group (5/sex) was reported and is consistent
with NTP guidelines for this study duration
Domain 5; Outcome Assessment
Metric 16;
Outcome Assessment Methodology
Metric 17; Consistency of Outcome Assessment
Metric 18; Sampling Adequacy
Metric 19; Blinding of Assessors
High All Outcomes: Absolute and relative organ weights were measured, and all animals
were subjected to gross necropsy. The outcome assessment methodologies were sensi-
tive to the outcome of interest.
High All Outcomes: Sufficient details of the outcome assessment protocols (organ weights
and histopathology) were provided, and outcome assessment was carried out consis-
tently across groups.
Medium All Outcomes: Organ weights were measured from all surviving animals. Histopathol-
ogy was conducted on controls and high-dose animals only, and no effects were ob-
served at the high dose. The methods suggest that all animals were examined, but
since negative findings were qualitatively reported, the sample size for this endpoint
(histopathology) cannot be verified.
N/A All Outcomes: Blinding is not required. The outcome is either not subjective in nature
(organ weights), or blinding is not required (initial histopathology).
Continued on next page ...
Page 50 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Cardiovascular; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspar-
tate aminotransferase, sorbitol dehydrogenase, cholesterol); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Renal/Kidney:
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/Respiratory; Gross necropsy, histopathology
(lung, nose, trachea); Immune/Hematological; Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 20;
Negative Control Response
Medium
All Outcomes: The appropriateness of the negative control response for histopathology
cannot be determined because the biological responses of the negative controls were not
reported. The control responses for organ weights were appropriate.
Domain 6; Confounding / Variable Control
Metric 21; Confounding Variables in Test Design
and Procedures
Metric 22; Health Outcomes Unrelated to
Exposure
Metric 23; Data Presentation and Analysis
Low All Outcomes: The initial body weights of female-treated mice were all significantly
higher (by 12% - 20% ) than the body weights of controls. This is confusing because an-
imals had been distributed into weight classes and then assigned to cages using random
numbers tables. It is unclear how the initial body weights of treated animals vs. controls
were different to the degree observed. The study authors did not comment on this. The
study did not measure food or water intake, but this was not a dietary or drinking water
study, and these endpoints are not required for this study type according to NTP. How-
ever, the treated animals gained significantly less body weight over the course of the
study than the controls. It is unknown if this was related to the fact that their initial body
weights were higher, or if there indeed had been decreases in food or water intake.
Medium Hepatic/Liver: There were three deaths attributed to gavage trauma. One male each
at 175and 350 mg/kg, and one female at 700 mg/kg. Other than reducing the sample
size, these deaths are not expected to have a significant impact on the study results. No
other health outcomes unrelated to exposure were reported.; Cardiovascular: There were
three deaths attributed to gavage trauma. One male each at 175 and 350 mg/kg, and one
female at 700 mg/kg. Other than reducing the sample size, these deaths are not expected
to have a significant impact on the study results. No other health outcomes unrelated to
exposure were reported.; Renal/Kidney: There were three deaths attributed to gavage
trauma. One male each at 175 and 350 mg/kg, and one female at 700 mg/kg. Other than
reducing the sample size, these deaths are not expected to have a significant impact on
the study results. No other health outcomes unrelated to exposure were reported.; Lung/
Respiratory: There were three deaths attributed to gavage trauma. One male each at
175and 350 mg/kg, and one female at 700 mg/kg. Other than reducing the sample size,
these deaths are not expected to have a significant impact on the study results. No other
health outcomes unrelated to exposure were reported.; Immune/Hematological: There
were three deaths attributed to gavage trauma. One male each at 175 and 350 mg/kg,
and one female at 700 mg/kg. Other than reducing the sample size, these deaths are not
expected to have a significant impact on the study results. No other health outcomes
unrelated to exposure were reported.
High All Outcomes: Statistical methods were adequately described and were appropriate for
the dataset. Statistical significance was shown where appropriate.
Continued on next page ...
Page 51 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Cardiovascular; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspar-
tate aminotransferase, sorbitol dehydrogenase, cholesterol); Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Renal/Kidney:
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/Respiratory; Gross necropsy, histopathology
(lung, nose, trachea); Immune/Hematological; Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric
Rating
Comments
Metric 24; Reporting of Data
High
All Outcomes: Organ weight data were reported quantitatively. Data were presented
as means ± SE. Negative gross necropsy and histopathological findings were reported
qualitatively in the text. The study reported that no gross observations or histopathologi-
cal lesions attributable to exposure were observed.
Overall Quality Determination
High
Page 52 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 9 of 11
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Short-term (> 1 -30 days) 16-days (mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% . The purity was both provided by the supplier and
confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were first assigned to weight groups and then, using random numbers tables,
animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
was also stable for 21 days in the dark at room temperature, or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium The doses were clearly reported. Animals were exposed to 0, 44, 88, 175, 350, or 700
mg/kg-day, 5 days per week. Time-adjusted doses were not reported but can be deter-
mined using the information available. Although dose formulations were analyzed for
accuracy in the 16-week and 2-yr experiments (also reported in this reference), there is
no indication that the doses in the 16-day study were analyzed.
High Animals were gavaged 5 days per week over 16 days for a total of 12 doses. Dosing 5
days per week for a gavage study is consistent with NTP guidelines.
High The study tested 5 exposure groups plus a control. The number of groups was consistent
with NTP guidelines. The dose spacing was adequate to allow for determination of
NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Continued on next page ...
Page 53 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 9 of 11
Domain
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Short-term (> 1 -30 days) 16-days (mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Metric
Rating
Comments
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9 weeks old), and initial body weights were reported
and appropriate.
Medium The number of animals per cage (5/cage) was reported. The NTP guideline specifies that
male mice should be housed individually for all studies. Food and water were provided
ad libiutm. Animal room environments (temperature, humidity, lighting were reported.
The humidity range was large (26% to 76% ). This deviates from NTP guidelines which
state humidity should not be below 35% or above 65% . It is unclear whether these
deviations had a significant impact on the study results.
Medium The number of animals per group (5/sex) was reported and is consistent with NTP
guidelines for this study duration
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High Serum Cholinesterase activity was determined at study termination. Absolute and rel-
ative organ weights were measured, and all animals were subjected to gross necropsy.
Brain tissue was examined histologically (other neuronal tissues were not examined).
The outcome assessment methodologies were sensitive to the outcome of interest.
High Sufficient details of the outcome assessment protocols (organ weights and histopathol-
ogy) were provided, and outcome assessment was carried out consistently across groups.
Blood for measurement of cholinesterase activity was collected from all animals at ter-
minal sacrifice.
Medium Organ weights were measured from all surviving animals. Histopathology was con-
ducted on controls and high-dose animals only, and no effects were observed at the high
dose. The methods suggest that all animals were examined, but since negative findings
were qualitatively reported, the sample size for this endpoint (histopathology) cannot be
verified.
N/A Blinding is not required. The outcome is either not subjective in nature (organ weights),
or blinding is not required (initial histopathology).
Medium The appropriateness of the negative control response for histopathology cannot be deter-
mined because the biological responses of the negative controls were not reported. The
control responses for organ weights and cholinesterase activity were appropriate.
Domain 6: Confounding / Variable Control
Continued on next page .
Page 54 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 9 of 11
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Short-term (> 1 -30 days) 16-days (mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 21:
Confounding Variables in Test Design
and Procedures
Low
The initial body weights of female-treated mice were all significantly higher (by 12%
- 20% ) than the body weights of controls. This is confusing because animals had been
distributed into weight classes and then assigned to cages using random numbers tables.
It is unclear how the initial body weights of treated animals vs. controls were different
to the degree observed. The study authors did not comment on this. The study did not
measure food or water intake, but this was not a dietary or drinking water study, and
these endpoints are not required for this study type according to NTP. However, the
treated animals gained significantly less body weight over the course of the study than
the controls. It is unknown if this was related to the fact that their initial body weights
were higher, or if there indeed had been decreases in food or water intake.
Metric 22:
Health Outcomes Unrelated to
Medium
There were three deaths attributed to gavage trauma. One male each at 175 and 350 mg/
Exposure
kg, and one female at 700 mg/kg. Other than reducing the sample size, these deaths are
not expected to have a significant impact on the study results. No other health outcomes
unrelated to exposure were reported.
Metric 23:
Data Presentation and Analysis
High
Statistical methods were adequately described and were appropriate for the dataset.
Statistical significance was shown where appropriate.
Metric 24:
Reporting of Data
Medium
Brain weight and serum cholinesterase data were reported quantitatively for both sexes
and all dose groups. Data were presented as means ± SE. Negative gross necropsy and
histopathological findings were reported qualitatively in the text. The study reported
that no gross observations or histopathological lesions attributable to exposure were
observed. No organ-specific results were reported. The text did report transient CNS-
related clinical signs the first three days of dosing; incidences and statistical significance
were not reported.
Overall Quality Determination
High
Page 55 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 10 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations
Clinical signs (clinical observations)
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High
High
High
The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was provided.
The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
The test chemical purity was 98% . The purity was both provided by the supplier and
confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High
N/A
Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were first assigned to weight groups and then, using random numbers tables,
animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
was also stable for 21 days in the dark at room temperature, or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days per week for
a total of 12 doses. Adjusted daily doses in mg/kg-day were not reported but can be
calculated using the information available. Although dose formulations were analyzed
for accuracy in the 16-week and 2-yr experiments (also reported in this reference), there
is no indication that the doses in the 16-day study were analyzed.
High Animals were gavaged 5 days per week over 16 days for a total of 12 doses. Dosing 5
days per week for a gavage study is consistent with NTP guidelines.
High The study tested 5 exposure groups plus a control. The number of groups was consistent
with NTP guidelines. The dose spacing was adequate to allow for determination of
NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Continued on next page .
Page 56 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 10 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations
Clinical signs (clinical observations)
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High
Medium
Medium
The study used male and female F344/N rats. The test animal source (Harlan indus-
tries), age at the start of the study (7 weeks), and initial body weights were reported and
appropriate.
The number of animals per cage (5/cage) was reported. Food and water were provided
ad libiutm. Animal room environments (temperature, humidity, lighting were reported.
The humidity varied considerably, ranging from 26% to 76% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is unclear
whether these deviations had any impact on the study results.
The number of animals per group (5/sex) was reported and is consistent with NTP
guidelines for this study duration
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Medium
Medium
Medium
Medium
Medium
Animals were observed daily for unspecified clinical signs. Limited details were avail-
able. The NTP guideline specifies that formal clinical signs shall be recorded daily by
animal number. It is unclear if this study did this; negative results were qualitatively
reported.
Based on the information provided, all animals were observed daily. Additional outcome
assessment methods (e.g., the time of observations (time of day)) were not provided,
but based on the available information, there is no indication that there were differences
across groups.
All animals were observed for clinical signs, but since negative findings were qualita-
tively reported, the sample size cannot be verified.
Blinding was not reported and clinical signs can be somewhat subjective in nature; how-
ever, lack of blinding is not expected to have a significant impact on results because no
clinical signs of toxicity were purportedly observed.
The appropriateness of the negative control response cannot be definitively determined
because incidence data were not reported, but the text indicates that no clinical signs
were observed.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design High The study did not measure food or water intake, but these but this was not a dietary or
and Procedures drinking water study, and these endpoints are not required for this study type according
to NTP. There were no significant body weight changes that were suggestive of palata-
bility issues.
Continued on next page ...
Page 57 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 10 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations
Clinical signs (clinical observations)
Short-term (>1-30 days) 16-days (rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 22:
Metric 23:
Metric 24:
Health Outcomes Unrelated to
Exposure
Data Presentation and Analysis
Reporting of Data
Uninformative
N/A
High
No animals died. Degenerative and inflammatory lesions characteristic of infection with
sialodacryoadenitis virus (SDA) were observed in the salivary glands and lungs of most
dosed and control rats. Because all groups appeared to be affected and it is unknown
how this infection may have impacted the study results, this study is considered to be
unacceptable.
Statistical analysis was not necessary; negative findings were qualitatively reported
across all groups.
Negative findings were qualitatively reported in the text.
Overall Quality Determination
Uninformative
Page 58 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 11 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations
Clinical signs (clinical observations)
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was provided.
Metric 2: Test Substance Source High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
Metric 3: Test Substance Purity High The test chemical purity was 98% . The purity was both provided by the supplier and
confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
N/A Positive controls are not required for this study type.
Medium Animals were first assigned to weight groups and then, using random numbers tables,
animals were were assigned to cages and then to groups.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
was also stable for 21 days in the dark at room temperature, or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium The doses were clearly reported. Animals were exposed to 0, 44, 88, 175, 350, or 700
mg/kg-day, 5 days per week. Time-adjusted doses were not reported but can be deter-
mined using the information available. Although dose formulations were analyzed for
accuracy in the 16-week and 2-yr experiments (also reported in this reference), there is
no indication that the doses in the 16-day study were analyzed.
High Animals were gavaged 5 days per week over 16 days for a total of 12 doses. Dosing 5
days per week for a gavage study is consistent with NTP guidelines.
High The study tested 5 exposure groups plus a control. The number of groups was consistent
with NTP guidelines. The dose spacing was adequate to allow for determination of
NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Continued on next page ...
Page 59 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 11 of 11
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations
Clinical signs (clinical observations)
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9 weeks old), and initial body weights were reported
and appropriate.
Medium The number of animals per cage (5/cage) was reported. The NTP guideline specifies that
male mice should be housed individually for all studies. Food and water were provided
ad libiutm. Animal room environments (temperature, humidity, lighting were reported.
The humidity range was large (26% to 76% ). This deviates from NTP guidelines which
state humidity should not be below 35% or above 65% . It is unclear whether these
deviations had a significant impact on the study results.
Medium The number of animals per group (5/sex) was reported and is consistent with NTP
guidelines for this study duration
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment Medium
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Medium Animals were observed daily for unspecified clinical signs. Limited details were avail-
able. The NTP guideline specifies that formal clinical signs shall be recorded daily by
animal number. It is unclear if this study did this, negative results were qualitatively
reported.
Based on the information provided, all animals were observed daily. Additional outcome
assessment methods (e.g., the time of observations (time of day)) were not provided,
but based on the available information, there is no indication that there were differences
across groups.
Medium Based on the study methods, all animals were observed for clinical signs, but since the
results were qualitatively reported, the sample size cannot be verified.
Medium Blinding was not reported and clinical signs can be somewhat subjective in nature; how-
ever, lack of blinding is not expected to have a significant impact on results because no
clinical signs of toxicity were observed.
Medium The appropriateness of the negative control response cannot be determined because the
biological responses of the negative controls were not reported.
Domain 6: Confounding / Variable Control
Continued on next page .
Page 60 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 11 of 11
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations
Clinical signs (clinical observations)
Short-term (>1-30 days) 16-days (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 21:
Confounding Variables in Test Design
and Procedures
Low
The initial body weights of female-treated mice were all significantly higher (by 12%
- 20% ) than the body weights of controls. This is confusing because animals had been
distributed into weight classes and then assigned to cages using random numbers tables.
It is unclear how the initial body weights of treated animals vs. controls were different
to the degree observed. The study authors did not comment on this. The study did not
measure food or water intake, but this was not a dietary or drinking water study, and
these endpoints are not required for this study type according to NTP. However, the
treated animals gained significantly less body weight over the course of the study than
the controls. It is unknown if this was related to the fact that their initial body weights
were higher, or if there indeed had been decreases in food or water intake.
Metric 22:
Health Outcomes Unrelated to
Medium
There were three deaths attributed to gavage trauma. One male each at 175 and 350 mg/
Exposure
kg, and one female at 700 mg/kg. Other than reducing the sample size, these deaths are
not expected to have a significant impact on the study results. No other health outcomes
unrelated to exposure were reported.
Metric 23:
Data Presentation and Analysis
High
Statistical methods were adequately described and were appropriate for the dataset.
Statistical significance was shown where appropriate.
Metric 24:
Reporting of Data
Low
Exposure-related findings were qualitatively described in the text. Statistical significance
was not specified.
Overall Quality Determination
High
Page 61 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469568 Table: 1 of 1
Study Citation: Sala, M„ Gu, Z. G„ Moens, G„ Chouroulinkov, I. (1982). In vivo and in vitro biological effects of the flame retardants tris(2,3-dibromopropyl) phosphate
and tris(2-chlorethyl)orthophosphate. European lournal of Cancer & Clinical Oncology 18( 12): 1337-1344.
Health Skin/Connective Tissue
Outcome(s):
Reported Health Short term skin test: mouse skin treated with TCEP showed that sebaceous glands were not suppressed and hyperplasia was not induced. Long term skin
Effect(s): test: mouse skin treated with TCEP showed negative results for complete carcinogenic or promoting activity on mouse skin.
Duration: Short-term (> 1 -30 days) Short term skin test
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469568
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
The substance was characterized by nomenclature and commercial name (i.e., Tris(2-
chloroethyl), orthophosphate; Genomoll P). The density (chemical property) was also
reported.
Metric 2:
Test Substance Source
High
Source: Hoechst
Metric 3:
Test Substance Purity
Low
Purity and/or grade of test substance were not reported.
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
High
Concurrent control groups were treated with vehicles: BP, TPA or acetone.
Metric 5:
Positive Controls
N/A
The study type does not require a positive control.
Metric 6:
Randomized Allocation of Animals
Low
The study did not report how animals were allocated to study groups.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Medium
There is an omission of details that are unlikely to have a substantial impact on results
Substance
(e.g. preparation/administration of test substance is described, but storage is not reported
however the assay is a short-term study and therefore storage is unlikely to affect re-
sults).
Metric 8:
Consistency of Exposure
High
Details of exposure administration were reported and exposures were administered
Administration
consistently across study groups.
Metric 9:
Reporting of Doses/Concentrations
High
Administered doses were reported without ambiguity.
Metric 10:
Exposure Frequency and Duration
High
The exposure frequency and duration of exposure were reported and appropriate for this
study type and/or outcome(s) of interest.
Metric 11:
Number of Exposure Groups and
Medium
There were three dose levels but it is unclear if highest dose was high enough.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
The route and method of exposure were reported and were suited to the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
High
The test animal species, strain, sex, age, and starting body weight were reported, and the
test animal was obtained from a commercial source or laboratory-maintained colony.
The test species and strain were an appropriate animal model for the evaluation of the
specific outcome(s) of interest (e.g., routinely used for similar study types).
Metric 14:
Adequacy and Consistency of Animal
Medium
Most husbandry conditions were not reported, but this is a short term study.
Husbandry Conditions
Metric 15:
Number of Animals per Group
Medium
25 female animals per dose group.
Continued on next page ...
Page 62 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469568 Table: 1 of 1
... continued from previous page
Study Citation: Sala, M„ Gu, Z. G„ Moens, G„ Chouroulinkov, I. (1982). In vivo and in vitro biological effects of the flame retardants tris(2,3-dibromopropyl) phosphate
and tris(2-chlorethyl)orthophosphate. European lournal of Cancer & Clinical Oncology 18( 12): 1337-1344.
Health Skin/Connective Tissue
Outcome(s):
Reported Health Short term skin test: mouse skin treated with TCEP showed that sebaceous glands were not suppressed and hyperplasia was not induced. Long term skin
Effect(s): test: mouse skin treated with TCEP showed negative results for complete carcinogenic or promoting activity on mouse skin.
Duration: Short-term (> 1 -30 days) Short term skin test
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469568
Domain
Metric
Rating
Comments
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
The outcome assessment methodology addressed the intended outcome(s) of interest
and the assessment methodology was sensitive and appropriate for the outcomes(s) of
interest.
Metric 17:
Consistency of Outcome Assessment
High
Outcomes were assessed consistently across study groups
Metric 18:
Sampling Adequacy
High
Reported information indicates the study used adequate sampling for the outcome(s) of
interest. Study authors refer to methods previously published in the literature.
Metric 19:
Blinding of Assessors
N/A
The number of sebaceous glands and the thickness of the epidermis were measured by
standard procedures.
Metric 20:
Negative Control Response
High
The biological responses of the negative control group(s) were adequate.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
Low
Body weight changes, food/water intake and differences in use of surgery were not
and Procedures
reported
Metric 22:
Health Outcomes Unrelated to
High
There were no adverse effects reported in control or treated animals.
Exposure
Metric 23:
Data Presentation and Analysis
High
To compare the mean values Student"s t-test was used, p-values were reported to show
statistical significance.
Metric 24:
Reporting of Data
High
Data for exposure-related findings were presented for all outcomes by exposure group.
Overall Quality Determination
High
Page 63 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 1 of 4
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Mortality
Mortality
Short-term (>1-30 days) Two doses - day 1 and day 21
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
Medium
No CASRN was identified but the name is specific enough to identify the exact struc-
ture.
The manufacturer was identified and chemical structure is not variable.
There was no information on purity.
Metric 2:
Metric 3:
Test Substance Source
Test Substance Purity
High
Low
Domain 2: Test Design
Metric 4:
Metric 5:
Metric 6:
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
Low
Medium
Low
The controls received corn oil but the dosed group received the test substance neat.
TOCP was used as a positive control and is appropriate for this test.
The study did not mention random allocation of animals.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Medium
There was limited/no info on preparation/storage but the chemical was administered
Substance
neat; it appears to be stable; and it was a short term study so it is not expected to result
in substantial effects.
Metric 8:
Consistency of Exposure
Medium
Corn oil in negative control vs. none in dose groups may result in some differences but
Administration
not likely to be substantial given that there was only one dose.
Metric 9:
Reporting of Doses/Concentrations
High
Doses were identified as g/kg.
Metric 10:
Exposure Frequency and Duration
High
Exposure frequency and duration were appropriate to the test.
Metric 11:
Number of Exposure Groups and
High
A limit test used a dose higher than required.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
The oral route was used and was acceptable.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Low
The source of the hens was not reported.
Metric 14:
Adequacy and Consistency of Animal
Medium
Most husbandry information was reported except humidity and whether the animals
Husbandry Conditions
were acclimatized before treatment (although the figure seems to indicate animals were
kept for several days before treatment).
Metric 15:
Number of Animals per Group
Medium
The number of animals were adequate - more than specified by the TG.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
Deaths are objective and easy to assess.
Metric 17:
Consistency of Outcome Assessment
High
Deaths easy to determine.
Continued on next page ...
Page 64 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 1 of 4
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Mortality
Mortality
Short-term (>1-30 days) Two doses - day 1 and day 21
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Domain
Metric
Rating
Comments
Metric 18:
Metric 19:
Sampling Adequacy
Blinding of Assessors
Metric 20: Negative Control Response
High All deaths were reported.
Medium Blinding of assessors is not reported but not crucial for objective measures (especially
deaths).
Low The authors note the possibility that mild neurological effects in the corn-oil treated
rats (controls) were reminiscent of Marek's disease (a neurological disease); it is not
clear whether this could have led to increases ONLY in the negative controls and thus
underestimated effects in the test animals. Presumably all animals came from the same
source and the treated groups also had the same possible Marek's disease but this is not
clear from the article.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
Metric 22:
Metric 23:
Metric 24:
and Procedures
Health Outcomes Unrelated to
Exposure
Data Presentation and Analysis
Reporting of Data
Medium
Medium
High
Medium
It is unclear how deviations from the protocol and use of corn oil only in controls may
have confounded outcomes but would not have been likely to affect whether animals
died.
The information on neurological effects on controls could have been related to Marek's
disease but details were limited on whether this had a differential effect and the severity
not likely to have an effect on deaths.
Statistical methods were described.
Number of deaths were reported but timing of those deaths was not recorded.
Overall Quality Determination
Medium
Page 65 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 2 of 4
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Neurological/Behavioral
Inhibition of plasma cholinesterase. Inhibition of neurotoxic esterase
Short-term (>1-30 days) Two doses - day 1 and day 21
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
Medium
No CASRN was identified but the name is specific enough to identify the exact struc-
ture.
The manufacturer was identified and chemical structure is not variable.
There was no information on purity.
Metric 2:
Metric 3:
Test Substance Source
Test Substance Purity
High
Low
Domain 2: Test Design
Metric 4:
Metric 5:
Metric 6:
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
Low
Medium
Low
The controls received corn oil but the dosed group received the test substance neat.
TOCP was used as a positive control and is appropriate for this test.
The study did not mention random allocation of animals.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Substance
Medium
There was limited/no info on preparation/storage but the chemical was administered
neat; it appears to be stable; and it was a short term study so it is not expected to result
in substantial effects.
Metric 8:
Consistency of Exposure
Administration
Medium
Corn oil in negative control vs. none in dose groups may result in some differences but
not likely to be substantial given that there was only one dose.
Metric 9:
Reporting of Doses/Concentrations
High
Doses were identified as g/kg.
Metric 10:
Exposure Frequency and Duration
High
Exposure frequency and duration were appropriate to the test.
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
High
A limit test used a dose higher than required.
Metric 12:
Exposure Route and Method
High
The oral route was used and was acceptable.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Low
The source of the hens was not reported.
Metric 14:
Adequacy and Consistency of Animal
Medium
Most husbandry information was reported except humidity and whether the animals
Husbandry Conditions
were acclimatized before treatment (although the figure seems to indicate animals were
kept for several days before treatment).
Metric 15:
Number of Animals per Group
Medium
The number of animals were adequate - more than specified by the TG.
Domain 5: Outcome Assessment
Continued on next page ...
Page 66 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 2 of 4
... continued from previous page
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Neurological/Behavioral
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Inhibition of plasma cholinesterase. Inhibition of neurotoxic esterase
Short-term (>1-30 days) Two doses - day 1 and day 21
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Metric
Rating
Metric
16:
Outcome Assessment Methodology
Low
Metric
17:
Consistency of Outcome Assessment
Medium
Metric
18:
Sampling Adequacy
Low
Metric
19:
Blinding of Assessors
Medium
Metric
20:
Negative Control Response
Low
Domain
Comments
The outcome assessment measured the midcervical vs. rostral cervical section of spinal
cord (unclear on difference). The animal preparation and staining appear appropriate to
identify the sections of the nervous system tissues. Neurobehavioral endpoints were very
limited; OPPTS 870.6100 (1998) states that forced motor activity should be measured
twice per week to see minimal changes and a 4-level rating scale should be used. Instead
the authors only note that they evaluated walking behavior once/week.
BW was measured every 3-4 days and walking behavior method not described but done
weekly.
5-18 hens were examined - unclear how sampling of hens was done and why these num-
bers varied (esp. down to 5 because controls/TOCP used 10 animals).
Blinding of assessors is not specified by the guidelines but examination of walking
behavior could be somewhat subjective.
The authors note the possibility that mild neurological effects in the corn-oil treated
rats (controls) were reminiscent of Marek's disease (a neurological disease); it is not
clear whether this could have led to increases ONLY in the negative controls and thus
underestimated effects in the test animals. Presumably all animals came from the same
source and the treated groups also had the same possible Marek's disease but this is not
clear from the article.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Low It is unclear how deviations from the protocol and use of corn oil only in controls may
have confounded outcomes.
Medium The information on neurological effects on controls could have been related to Marek's
disease but details were limited on whether this had a differential effect.
High Statistical methods were described.
Low Only limited details reported on 'walking behavior'
Overall Quality Determination
Medium
Page 67 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 3 of 4
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Skin/Connective Tissue
Feather loss
Short-term (>1-30 days) Two doses - day 1 and day 21
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
Medium
No CASRN was identified but the name is specific enough to identify the exact struc-
ture.
The manufacturer was identified and chemical structure is not variable.
There was no information on purity.
Metric 2:
Metric 3:
Test Substance Source
Test Substance Purity
High
Low
Domain 2: Test Design
Metric 4:
Metric 5:
Metric 6:
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
Low
Medium
Low
The controls received corn oil but the dosed group received the test substance neat.
TOCP was used as a positive control and is appropriate for this test.
The study did not mention random allocation of animals.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Substance
Medium
There was limited/no info on preparation/storage but the chemical was administered
neat; it appears to be stable; and it was a short term study so it is not expected to result
in substantial effects.
Metric 8:
Consistency of Exposure
Administration
Medium
Corn oil in negative control vs. none in dose groups may result in some differences but
not likely to be substantial given that there was only one dose.
Metric 9:
Reporting of Doses/Concentrations
High
Doses were identified as g/kg.
Metric 10:
Exposure Frequency and Duration
High
Exposure frequency and duration were appropriate to the test.
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
High
A limit test used a dose higher than required.
Metric 12:
Exposure Route and Method
High
The oral route was used and was acceptable.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Low
The source of the hens was not reported.
Metric 14:
Adequacy and Consistency of Animal
Medium
Most husbandry information was reported except humidity and whether the animals
Husbandry Conditions
were acclimatized before treatment (although the figure seems to indicate animals were
kept for several days before treatment).
Metric 15:
Number of Animals per Group
Medium
The number of animals were adequate - more than specified by the TG.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Low
Not clear when animals were examined for skin/other conditions, clinical signs.
Metric 17:
Consistency of Outcome Assessment
Medium
Not clear whether animals were examined at different times but severe feather loss oc-
curred in treated animals so lack of details should not significantly affect outcomes.
Continued on next page ...
Page 68 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 3 of 4
... continued from previous page
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Skin/Connective Tissue
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Feather loss
Short-term (>1-30 days) Two doses - day 1 and day 21
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Domain
Metric
Rating
Comments
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Low 5-18 animals were sampled with no further explanation about why some groups used
less than the number of animals tested. This discrepancy is not explained fully by #
deaths.
Medium Blinding of assessors not reported, but not required by the OPPTS 870.6100 guideline.
Identification of severe feather loss not likely to be affected by lack of blinding.
Medium The authors note the possibility that mild neurological effects in the corn-oil treated rats
(controls) were reminiscent of Marek's disease (a neurological disease). Presumably all
animals came from the same source and the treated groups also had the same possible
Marek's disease but this is not clear from the article. Severe feather loss occurred only in
treated groups so this would not likely affect the outcome.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Medium There were deviations from the protocol and use of corn oil only in controls but not
likely to affect outcomes because the severe feather loss occurred only in treated groups.
Medium The information on neurological effects on controls could have been related to Marek's
disease but details were limited on whether this had a differential effect but not likely to
affect the outcome of severe feather loss in treated groups.
High Statistical methods were described.
Low Timing of feather loss was somewhat unclear; incidence per group not given.
Overall Quality Determination
Medium
Page 69 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 4 of 4
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Nutritional/Metabolic
Body weightFood consumption
Short-term (>1-30 days) Two doses - day 1 and day 21
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
Medium
No CASRN was identified but the name is specific enough to identify the exact struc-
ture.
The manufacturer was identified and chemical structure is not variable.
There was no information on purity.
Metric 2:
Metric 3:
Test Substance Source
Test Substance Purity
High
Low
Domain 2: Test Design
Metric 4:
Metric 5:
Metric 6:
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
Low
Medium
Low
The controls received corn oil but the dosed group received the test substance neat.
TOCP was used as a positive control and is appropriate for this test.
The study did not mention random allocation of animals.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Substance
Medium
There was limited/no info on preparation/storage but the chemical was administered
neat; it appears to be stable; and it was a short term study so it is not expected to result
in substantial effects.
Metric 8:
Consistency of Exposure
Administration
Medium
Corn oil in negative control vs. none in dose groups may result in some differences but
not likely to be substantial given that there was only one dose.
Metric 9:
Reporting of Doses/Concentrations
High
Doses were identified as g/kg.
Metric 10:
Exposure Frequency and Duration
High
Exposure frequency and duration were appropriate to the test.
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
High
A limit test used a dose higher than required.
Metric 12:
Exposure Route and Method
High
The oral route was used and was acceptable.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Low
The source of the hens was not reported.
Metric 14:
Adequacy and Consistency of Animal
Medium
Most husbandry information was reported except humidity and whether the animals
Husbandry Conditions
were acclimatized before treatment (although the figure seems to indicate animals were
kept for several days before treatment).
Metric 15:
Number of Animals per Group
Medium
The number of animals were adequate - more than specified by the TG.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Medium
BW and food consumption were measured every 3-4 days.
Metric 17:
Consistency of Outcome Assessment
Medium
Few details about when collection was made (every 3-4 days) without stating whether
this was consistent between controls/dose groups.
Continued on next page ...
Page 70 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 656590 Table: 4 of 4
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sprague, G. L„ Sandvik, L. L., Brookins-Hendricks, M. J., Bickford, A. A. (1981). Neurotoxicity of two organophosphorus ester flame retardants in hens.
Journal of Toxicology and Environmental Health, Part A: Current Issues 8(3 ):507-518.
Nutritional/Metabolic
Body weightFood consumption
Short-term (>1-30 days) Two doses - day 1 and day 21
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
656590
Domain
Metric
Rating
Comments
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High
Medium
Low
5-18 animals were sampled with no further explanation about why some groups used
less than the number of animals tested. Although some animals died, the numbers of
deaths don't fully describe the discrepancy in # animals sampled/group.
Blinding of assessors is less important for objective measures.
The authors note the possibility that mild neurological effects in the corn-oil treated rats
(controls) were reminiscent of Marek's disease (a neurological disease). Presumably all
animals came from the same source and the treated groups also had the same possible
Marek's disease but this is not clear from the article.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
Metric 22:
Metric 23:
Metric 24:
and Procedures
Health Outcomes Unrelated to
Exposure
Data Presentation and Analysis
Reporting of Data
Low It is unclear how deviations from the protocol and use of corn oil only in controls may
have confounded outcomes.
Medium The information on neurological effects on controls could have been related to Marek's
disease but details were limited on whether this had a differential effect and the severity
not likely to have an effect on BW and food consumption.
High Statistical methods were described.
Low BW and food consumption were reported only on separate graphs for controls vs. the
dosed group and there was no separate table outlining all results. Thus, it was difficult to
compare results between groups.
Overall Quality Determination
Medium
Page 71 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469208 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Taniai, E„ Hayashi, H„ Yafune, A., Watanabe, M., Akane, H., Suzuki, K„ Mitsumori, K„ Shibutani, M. (2012). Cellular distribution of cell cycle-related
molecules in the renal tubules of rats treated with renal carcinogens for 28 days: relationship between cell cycle aberration and carcinogenesis. Archives
of Toxicology 86(9): 1453-1464.
Renal/Kidney
Immunohistochemical analysis of tubular cells was used to investigate cell cycle-related changes during the early stages of renal carcinogenesis.
Short-term (>1-30 days) 28 days
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469208
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High Test substance was identified as tris(2-chloroethyl) phosphate (CAS No. 115-96-8)
High Test substance was purchased from Tokyo Chemical Industry Co. (Tokyo, Japan).
Batch/lot number was not reported.
High Test substance purity was reported as >97%
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
Low
N/A
Medium
Authors state "Ten untreated control animals were maintained with basal diet and tap
water without any treatment during the experimental period." TCEP was dissolved in
corn oil and administered via gavage. It is unclear if a corn oil control was used.
Positive controls are not needed for this study type.
Study authors state "After 1-week acclimatization period, animals were randomized into
groups of 10 animals"
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Medium
Study authors state that TCEP was dissolved in corn oil. No further details regarding test
Substance
substance preparation or storage were provided.
Metric 8:
Consistency of Exposure
Medium
TCEP was administered daily by gavage. No details on timing of administration or
Administration
gavage volume were provided.
Metric 9:
Reporting of Doses/Concentrations
High
Doses (0 and 350 mg/kg-d) were reported without ambiguity.
Metric 10:
Exposure Frequency and Duration
High
Animals were administered TCEP for 28 consecutive days.
Metric 11:
Number of Exposure Groups and
N/A
N/A. The goal of this mechanistic study was not to observe a dose-response.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
TCEP was dissolved in corn oil and administered via oral gavage.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics Medium
Metric 14: Adequacy and Consistency of Animal High
Husbandry Conditions
Metric 15: Number of Animals per Group Medium
Five week old male F344/NSIc rats were purchased from Japan SLC, Inc (Hamamatsu,
Japan). Starting body weight was not reported.
All husbandry conditions were reported (e.g., temperature, humidity, light- dark cycle,
diet, water availability) and were adequate.
10 animals were included per group. This is appropriate for a 28-day study.
Domain 5: Outcome Assessment
Continued on next page ...
Page 72 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469208 Table: 1 of 1
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Taniai, E„ Hayashi, H„ Yafune, A., Watanabe, M., Akane, H., Suzuki, K„ Mitsumori, K„ Shibutani, M. (2012). Cellular distribution of cell cycle-related
molecules in the renal tubules of rats treated with renal carcinogens for 28 days: relationship between cell cycle aberration and carcinogenesis. Archives
of Toxicology 86(9): 1453-1464.
Renal/Kidney
Immunohistochemical analysis of tubular cells was used to investigate cell cycle-related changes during the early stages of renal carcinogenesis.
Short-term (>1-30 days) 28 days
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469208
Domain
Metric
Rating
Comments
Metric
16:
Outcome Assessment Methodology
Metric
17:
Consistency of Outcome Assessment
Metric
18:
Sampling Adequacy
Metric
19:
Blinding of Assessors
Metric
20:
Negative Control Response
High The outcome assessment methodology adequately addressed the outcome of interest.
High One day after the 28-day treatment, all animals were sacrificed and kidneys were re-
moved for histopathological and immunohistochemical examination
High The ten animals included in each treatment group were evaluated for each outcome of
interest.
N/A Blinding is not necessary for initial histopathology review.
Medium Biological responses were only reported for some outcomes of interest (i.e., histochem-
ical analyses). Histopathological response data was not reported for the negative control
group.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Low Confounding variables (i.e., body weight, food/water intake values) were not reported.
Medium There was no information either to support or dismiss the suggestion that there were
differences among groups in animal attrition or health outcomes unrelated to exposure
that could influence the outcome assessment.
Low Statistical methods were clearly described for some outcomes (immunohistochemical
analysis). However, it is unclear if a statistical analysis was conducted on the observed
histopathological changes.
Low Immunohistochemical data is represented graphically as mean +/- standard deviation.
A limited description of histopathological findings is described qualitatively in the text,
however, incidence data is not provided.
Overall Quality Determination
Medium
Page 73 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469521 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Taniai, E„ Yafune, A., Hayashi, H„ Itahashi, M„ Hara-Kudo, Y., Suzuki, K„ Mitsumori, K., Shibutani, M. (2012). Aberrant activation of ubiquitin D at G2
phase and apoptosis by carcinogens that evoke cell proliferation after 28-day administration in rats. Journal of Toxicological Sciences 37(6): 1093-1111.
Cancer/Carcinogenesis
Kidney cancer (aim was to identify early prediction markers of carcinogenesis)
Short-term (>1-30 days) 28-day oral gavage study
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469521
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High Test substance identified as tris(2-chloroethyl)phosphate (Cas No. 115-96-8)
High Test substance was obtained from Tokylo Chemical Industry Corporation (Tokyo,
Japan). Batch/lot number were not provided.
High Purity of test substance was reported as >97.0%
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
Low
N/A
Medium
Untreated controls were used. Figure 1, which outlines the experimental design, in-
dicates that control animals were fed basal diet and tap water. However, TCEP was
dissolved in corn oil and administered via gavage. Insufficient details are provided to
determine if control animals were gavaged with corn oil.
Not applicable for this study type.
Study authors state that "animals were randomized into groups of 10 each and treated
with carcinogens for non-carcinogens for 28-days"
Domain 3: Exposure Characterization
Metric
7:
Preparation and Storage of Test
Substance
Medium
Study authors state that TCEP was dissolved in corn oil. No additional information on
preparation or storage of the test substance was provided.
Metric
8:
Consistency of Exposure
Administration
Low
Details of exposure administration are insufficiently reported. No information on gavage
volume or timing of test substance administration were reported.
Metric
9:
Reporting of Doses/Concentrations
High
Doses (0 and 350 mg/kg-d) were reported without ambiguity.
Metric
10:
Exposure Frequency and Duration
High
TCEP was administered daily for 28 consecutive days. This frequency and duration was
considered appropriate for the aim of the study (i.e., to identify early prediction markers
of carcinogens).
Metric
11:
Number of Exposure Groups and
Dose/Concentration Spacing
N/A
Not applicable. The goal of the study was to identify early prediction markers of car-
cinogens, not to achieve a dose-resposne.
Metric
12:
Exposure Route and Method
High
Test substance was administered via oral gavage.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics Medium
Metric 14: Adequacy and Consistency of Animal High
Husbandry Conditions
Five week old male F344/NSIc rats were obtained from Japan SLC, Inc. (Shizouka,
Japan). They were housed in stainless steel cages in a barrier-maintained animal room
on a 12 hr light-dark cycle and conditioned at 23C (+/- 3C) with a relative humidity of
50% (+/-20% ). Animal starting body weight was not reported.
All husbandry conditions were reported and were adequate.
Continued on next page ...
Page 74 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469521 Table: 1 of 1
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Taniai, E„ Yafune, A., Hayashi, H„ Itahashi, M„ Hara-Kudo, Y., Suzuki, K„ Mitsumori, K., Shibutani, M. (2012). Aberrant activation of ubiquitin D at G2
phase and apoptosis by carcinogens that evoke cell proliferation after 28-day administration in rats. Journal of Toxicological Sciences 37(6): 1093-1111.
Cancer/Carcinogenesis
Kidney cancer (aim was to identify early prediction markers of carcinogenesis)
Short-term (>1-30 days) 28-day oral gavage study
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469521
Domain
Metric
Rating
Comments
Metric 15:
Number of Animals per Group
Medium
10 rats were included in each treatment group.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
The methodology addressed the intended outcomes.
Metric 17:
Consistency of Outcome Assessment
High
One day after the 28-day treatment, all animals were sacrificed and kidneys are removed
for histopathological and immunohistochemical examination.
Metric 18:
Sampling Adequacy
High
Kidneys were evaluated from all 10 animals treated with TCEP.
Metric 19:
Blinding of Assessors
N/A
Blinding is not necessary for initial histopathology review.
Metric 20:
Negative Control Response
Low
The biological response of the negative control groups were not reported for all out-
comes (i.e., histopathology).
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Medium No information on animal body or food/water intake were reported.
Medium There was no information either to support or dismiss the suggestion that there were
differences among groups in animal attrition or health outcomes unrelated to exposure
that could influence the outcome assessment.
Low Statistical analysis was clearly described and appropriate for the immunohistochemical
staining of kidney cells. Study authors report that TCEP treatment resulted in scattered
proximal tubular regeneration in the cortex and OSOM; however, it is unclear if a statis-
tical analysis was performed on the histopathological findings.
Low Data for immunohistochemical staining for Mcm3+, Ubd+ and TUNEL+ cells is pre-
sented graphically as mean plus standard deviation. Histopathological findings were
described qualitatively in the study report, however, incidence data is not provided.
Overall Quality Determination
Medium
Page 75 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 4199395 Table: 1 of 2
Study Citation: Chen, G„ Jin, Y., Wu, Y., Liu, L„ Fu, Z, (2015), Exposure of male mice to two kinds of organophosphate flame retardants (OPFRs) induced oxidative
stress and endocrine disruption. Environmental Toxicology and Pharmacology 40(1 ):310-318,
Health Hepatic/Liver; Nutritional/Metabolic;
Outcome(s):
Reported Health Hepatic/Liver: Decreased liver weights, decreased hepatic glutathione (GSH)content, altered activities of hepatic enzymes including glutathione peroxidase
Effect(s): (GPX), catalase (CAT) and glutathione S-transferase (GST), altered transcriptional patterns of Sodl, Sod2, Gpxl, Gpx2 and Cat,; Nutritional/Metabolic:
Decreased in weights,;
Duration: Subchronic (>30-91 days) 35 days
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 4199395
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Metric 2:
Metric 3:
Test Substance Identity
Test Substance Source
Test Substance Purity
High
High
High
All Outcomes: The test substance was identified definitively.
All Outcomes: The source of the test substance was reported.
All Outcomes: The purity was reported as >97% .
Domain 2: Test Design
Metric 4:
Metric 5:
Metric 6:
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
High
N/A
Medium
All Outcomes: Control animals were given standard diet.
All Outcomes: A positive control is not needed for this study type.
All Outcomes: The study reported that animals were randomly allocated into study
groups.
Domain 3: Exposure Characterization
Metric
7:
Metric
8:
Metric
9:
Metric
10:
Metric
11:
Metric
12:
Preparation and Storage of Test
Substance
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
Exposure Frequency and Duration
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
Medium All Outcomes: No information on storage conditions of mixed diet or stability and ho-
mogeneity.
High All Outcomes: Details of exposure administration were reported and exposures were
administered consistently across study groups.
Low All Outcomes: Nominal dose was provided rather than the analytical dose and no infor-
mation was provided on food consumption.
High All Outcomes: The exposure frequency and duration of exposure were reported and
appropriate for this study type.
Medium All Outcomes: There were minor limitations regarding the number of exposure groups
and/or dose/concentration spacing (i.e., effects were observed at all doses tested).
High All Outcomes: The route and method of exposure were reported and were suited to the
test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics High
Metric 14: Adequacy and Consistency of Animal High
Husbandry Conditions
Metric 15: Number of Animals per Group Low
All Outcomes: The test animal species, strain, sex, age, and starting body weight were
reported.
All Outcomes: Husbandry conditions were reported and were appropriate.
All Outcomes: There were 7 animals per study group. The standard for subchronic
studies is 10 animals per group.
Continued on next page ...
Page 76 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 4199395 Table: 1 of 2
... continued from previous page
Study Citation: Chen, G„ Jin, Y., Wu, Y., Liu, L„ Fu, Z, (2015), Exposure of male mice to two kinds of organophosphate flame retardants (OPFRs) induced oxidative
stress and endocrine disruption. Environmental Toxicology and Pharmacology 40(1 ):310-318,
Health Hepatic/Liver; Nutritional/Metabolic;
Outcome(s):
Reported Health Hepatic/Liver: Decreased liver weights, decreased hepatic glutathione (GSH)content, altered activities of hepatic enzymes including glutathione peroxidase
Effect(s): (GPX), catalase (CAT) and glutathione S-transferase (GST), altered transcriptional patterns of Sodl, Sod2, Gpxl, Gpx2 and Cat,; Nutritional/Metabolic:
Decreased in weights,;
Duration: Subchronic (>30-91 days) 35 days
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 4199395
Domain
Metric
Rating
Comments
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
All Outcomes: The outcome assessment methodology addressed the intended out-
come^) of interest.
Metric 17:
Consistency of Outcome Assessment
High
All Outcomes: Details of the outcome assessment protocol were reported and outcomes
were assessed consistently across study groups.
Metric 18:
Sampling Adequacy
High
Hepatic/Liver: For liver endpoints, n=7 animals per group; Nutritional/Metabolic: n=7
animals per group
Metric 19:
Blinding of Assessors
N/A
Hepatic/Liver: Blinding was not required for liver endpoints.; Nutritional/Metabolic:
Blinding was not required for body weight and food intake.
Metric 20:
Negative Control Response
High
All Outcomes: The biological responses of the negative control group was adequate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Low Hepatic/Liver: The study does not report food intake. It is not clear whether reduced
body weight and liver weights are treatment related or due to reduced food intake. Rela-
tive liver weights are not reported, making it difficult to determine whether liver weight
changes are proportional to body weight changes or an effect that is specific to the liver.;
Nutritional/Metabolic: The study does not report food intake, making it difficult to de-
termine the extent to which body weight reduction may be due to reduced consumption
or impacts on food efficiency.
High All Outcomes: There were no differences among groups that could influence the out-
come assessment.
High All Outcomes: Statistical methods were clearly described and appropriate.
Medium All Outcomes: Most data was only provided in charts.
Overall Quality Determination
High
Page 77 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 4199395 Table: 2 of 2
Study Citation: Chen, G„ Jin, Y., Wu, Y., Liu, L„ Fu, Z, (2015), Exposure of male mice to two kinds of organophosphate flame retardants (OPFRs) induced oxidative
stress and endocrine disruption. Environmental Toxicology and Pharmacology 40(1 ):310-318,
Health Reproductive/Developmental
Outcome(s):
Reported Health Decreased testis weights, decrease of testicular testosterone level, decreased gene expression of genes related to testosterone synthesis, histopathological
Effect(s): damage (decreased number of leydig cells, Sertoli cells and spermatogenic cells, and disintegration of seminiferous tubule structure at 300 mg/kg TCEP),
Duration: Subchronic (>30-91 days) 35 days
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 4199395
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
The test substance was identified definitively.
Metric 2:
Test Substance Source
High
The source of the test substance was reported.
Metric 3:
Test Substance Purity
High
The purity was reported as >97% .
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
High
Control animals were given standard diet.
Metric 5:
Positive Controls
N/A
A positive control is not needed for this study type.
Metric 6:
Randomized Allocation of Animals
Medium
The study reported that animals were randomly allocated into study groups.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Medium
No information on storage conditions of mixed diet or stability and homogeneity.
Substance
Metric 8:
Consistency of Exposure
High
Details of exposure administration were reported and exposures were administered
Administration
consistently across study groups.
Metric 9:
Reporting of Doses/Concentrations
Low
Nominal dose was provided rather than the analytical dose and no information was
provided on food consumption.
Metric 10:
Exposure Frequency and Duration
High
The exposure frequency and duration of exposure were reported and appropriate for this
study type.
Metric 11:
Number of Exposure Groups and
Medium
There were minor limitations regarding the number of exposure groups and/or dose/
Dose/Concentration Spacing
concentration spacing (i.e., effects were observed at all doses tested).
Metric 12:
Exposure Route and Method
High
The route and method of exposure were reported and were suited to the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
High
The test animal species, strain, sex, age, and starting body weight were reported.
Metric 14:
Adequacy and Consistency of Animal
High
Husbandry conditions were reported and were appropriate.
Husbandry Conditions
Metric 15:
Number of Animals per Group
Low
There were 7 animals per study group. The standard for subchronic studies is 10 animals
per group.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
The outcome assessment methodology addressed the intended outcome(s) of interest.
Metric 17:
Consistency of Outcome Assessment
High
Details of the outcome assessment protocol were reported and outcomes were assessed
consistently across study groups.
Metric 18:
Sampling Adequacy
Low
For testis weight n=7; for histopathological evaluation, n= 2
Continued on next page ...
Page 78 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 4199395 Table: 2 of 2
... continued from previous page
Chen, G„ Jin, Y., Wu, Y., Liu, L„ Fu, Z, (2015), Exposure of male mice to two kinds of organophosphate flame retardants (OPFRs) induced oxidative
stress and endocrine disruption. Environmental Toxicology and Pharmacology 40(1 ):310-318,
Reproductive/Developmental
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Decreased testis weights, decrease of testicular testosterone level, decreased gene expression of genes related to testosterone synthesis, histopathological
damage (decreased number of leydig cells, Sertoli cells and spermatogenic cells, and disintegration of seminiferous tubule structure at 300 mg/kg TCEP),
Subchronic (>30-91 days) 35 days
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
4199395
Domain
Metric
Rating
Comments
Metric 19:
Blinding of Assessors
N/A
Histological evaluations relied on quantitative metrics (the number of seminiferous
tubules).
Metric 20:
Negative Control Response
High
The biological responses of the negative control group was adequate.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
Low
The study does not report food intake, making it difficult to determine the extent to
and Procedures
which body weight reduction, reduced organ weights, and other effects may be due to
reduced consumption.
Metric 22:
Health Outcomes Unrelated to
High
There were no differences among groups that could influence the outcome assessment.
Exposure
Metric 23:
Data Presentation and Analysis
High
Statistical methods were clearly described and appropriate.
Metric 24:
Reporting of Data
Medium
Most data was only provided in charts.
Overall Quality Determination
High
Page 79 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469245 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Yang, W„ Zhao, F., Fang, Y„ Li, L„ Li, C„ Ta, N, (2018), lH-nuclear magnetic resonance metabolomics revealing the intrinsic relationships between neuro-
chemical alterations and neurobehavioral and neuropathological abnormalities in rats exposed to tris(2-chloroethyl)phosphate. Chemosphere 200:649-659,
Neurological/Behavioral
Neurotoxic effects (neurochemical alterations, neurobehavioral and neuropathological abnormalities) Neurochemical alterations (dose-dependent increase
in alterations of amino acid and neurotransmitter metabolism, energy metabolism, and cell membrane integrity )Neurobehavioral and neuropathological
abnormalities (degeneration, necrosis, and loss of neurons in the hippocampal CA1 region of rats), these alterations can lead to functional disorder of
learning and memory,
Subchronic (>30-91 days) 60-day oral exposure
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469245
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
Identified definitively with nomenclature, CASRN, and structure.
Metric 2:
Test Substance Source
High
Source was provided and identified as a manufacturer.
Metric 3:
Test Substance Purity
High
Purity was reported as >95% .
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
High
Control animals were administered corn oil.
Metric 5:
Positive Controls
N/A
Positive controls were not needed for this study design.
Metric 6:
Randomized Allocation of Animals
Low
The only detail provided was that littermates were not used in the same experimental
group. Unlikely to have a substantial impact.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
Medium
Storage is not reported, but unlikely to have substantial impacts.
Substance
Metric 8:
Consistency of Exposure
Medium
Information is not provided on the volume of corn oil used for the controls or gavage
Administration
administration of the treated groups.
Metric 9:
Reporting of Doses/Concentrations
Medium
Only nominal doses were reported.
Metric 10:
Exposure Frequency and Duration
High
The exposure frequency and duration of exposure were reported and appropriate for this
study type and/or outcomes of interest.
Metric 11:
Number of Exposure Groups and
High
A control and three treatment groups were used.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
Oral gavage is a relevant route of administration. However, a bolus dose may not be
relevant for all exposure pathways.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Medium
Starting body weight was not provided, but unlikely to have a substantial effects on the
outcomes measured in this study.
Metric 14:
Adequacy and Consistency of Animal
High
Temperature, humidity, light- dark cycle, diet, and food and water availability were all
Husbandry Conditions
reported.
Metric 15:
Number of Animals per Group
Medium
The number of animals was not explicitly stated but was reported to be 10 in may of the
data tables.
Continued on next page ...
Page 80 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469245 Table: 1 of 1
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Yang, W„ Zhao, F., Fang, Y„ Li, L„ Li, C„ Ta, N, (2018), lH-nuclear magnetic resonance metabolomics revealing the intrinsic relationships between neuro-
chemical alterations and neurobehavioral and neuropathological abnormalities in rats exposed to tris(2-chloroethyl)phosphate. Chemosphere 200:649-659,
Neurological/Behavioral
Neurotoxic effects (neurochemical alterations, neurobehavioral and neuropathological abnormalities) Neurochemical alterations (dose-dependent increase
in alterations of amino acid and neurotransmitter metabolism, energy metabolism, and cell membrane integrity )Neurobehavioral and neuropathological
abnormalities (degeneration, necrosis, and loss of neurons in the hippocampal CA1 region of rats), these alterations can lead to functional disorder of
learning and memory,
Subchronic (>30-91 days) 60-day oral exposure
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469245
Domain
Metric
Rating
Comments
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
10 animals per group
Metric 17:
Consistency of Outcome Assessment
High
Outcomes were assessed consistently across study groups.
Metric 18:
Sampling Adequacy
High
The study used adequate sampling for the outcomes of interest.
Metric 19:
Blinding of Assessors
High
The study did not report whether assessors were blinded to treatment group, however,
the outcomes that were assessed are not subjective.
Metric 20:
Negative Control Response
High
The biological responses of the negative control groups were adequate.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
Medium
Although the study did not report all information to determine confounding, the reported
and Procedures
information did not identify differences.
Metric 22:
Health Outcomes Unrelated to
High
There were no differences reported among groups that could influence the outcome
Exposure
assessment.
Metric 23:
Data Presentation and Analysis
High
Statistical methods were clearly described.
Metric 24:
Reporting of Data
Medium
Data for exposure-related findings were presented for most outcomes. However,
histopathological results were not adequately described.
Overall Quality Determination
High
Page 81 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 1 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Nutritional/Metabolic; Nutritional/Metabolic;
Nutritional/Metabolic: Body weight; Nutritional/Metabolic: Body weight;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain Metric Rating Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity High All Outcomes: The test substance was clearly identified as tris(2-chloroethyl)phosphate.
Metric 2: Test Substance Source High All Outcomes: The test substance was purchased from Stauffer Chemical Company. The
lot and batch number were provided.
Metric 3: Test Substance Purity Low All Outcomes: The purity was not reported and could not be determined on the manu-
facturer's website.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High All Outcomes: The study included a concurrent negative vehicle (corn oil) control
group.
N/A All Outcomes: Positive controls are not necessary for this study type.
Medium All Outcomes: Animals were assigned to dose groups and to cages using a random
number table. It was not specified whether animals were also normalized to starting
body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11:
Metric 12:
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
Medium All Outcomes: Fresh solutions were made every two weeks by dissolving the test mate-
rial in 100% pure corn oil. Test solutions were stored at 5 degrees C until use. Details of
mixing for homogeneity weren't provided. Testing for stability was not discussed.
High All Outcomes: Sufficient exposure administration details were reported. A consistent
gavage volume of 5 mL/kg was used. The time of day of dosing was not specified.
Medium All Outcomes: Doses were clearly reported. Dosing solutions were analyzed (method
and frequency not specified), and the text indicated that the actual concentrations admin-
istered remained within 10% of the target. Analytical values were not provided.
Medium All Outcomes: The study did not mention adherence to a specific guideline, but the text
indicated this was an NTP study. Animals were dosed 5 days per week, consistent with
the "Specifications for the Conduct of Studies to Evaluate the Toxic and Carcinogenic
Potential of Chemical, Biological and Physical Agents in Laboratory Animals for the
National Toxicology Program (NTP). The study duration was 16 weeks. The authors
did not provide justification for this duration. This is longer than a typical 90-day sub-
chronic study, and shorter than an NTP chronic/carcinogenicity study.
High All Outcomes: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Continued on next page ...
Page 82 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 1 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Nutritional/Metabolic; Nutritional/Metabolic;
Nutritional/Metabolic: Body weight; Nutritional/Metabolic: Body weight;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 4: Test Animals
Metric 13: Test Animal Characteristics Medium Nutritional/Metabolic: The study used male and female F344/N rats. The test animal
source (Charles River Breeding Laboratories), and age purchase (5 weeks old), were
reported. Initial body weights were not specified. A quarantine period was mentioned,
but the duration was not reported.; Nutritional/Metabolic: The study used male and
female B6C3F1 mice. The test animal source (Charles River Breeding Laboratories),
and age purchase (5 weeks old), were reported. Initial body weights were not specified.
A quarantine period was mentioned, but the duration was not reported.
Metric 14: Adequacy and Consistency of Animal Medium Nutritional/Metabolic: Animal husbandry (caging, food and water access, temperature,
Husbandry Conditions humidity, and light cycle) were reported. The relative humidity varied from 10% to
78% . This deviates from NTP guidelines that stat humidity should not be below 35%
or above 65% . The temperature range in the study was 70 to 81 degrees. NTP indicates
temperature should not be above 75 degrees, and that there should be minimal fluctu-
ations. The number of animals per cage (n =5) was appropriate. It is unclear whether
the deviations in animal husbandry conditions had an impact on the study results.; Nu-
tritional/Metabolic: Animal husbandry (caging, food and water access, temperature,
humidity, and light cycle) were reported. The relative humidity varied from 10% to 78%
. This deviates from NTP guidelines that state humidity should not be below 35% or
above 65% . The temperature range in the study was 70 to 81 degrees. NTP indicates
temperature should not be above 75 degrees, and that there should be minimal fluctua-
tions. The number of animals per cage (n =5) was reported. NTP guidelines specify that
male mice should always be housed individually. It is unclear whether the deviations in
animal husbandry conditions had an impact on the study results.
Metric 15: Number of Animals per Group Medium All Outcomes: The number of animals per group (10/sex) was reported and consistent
with NTP guidelines.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
High All Outcomes: The text indicated that body weights were recorded weekly and body
weight gain was determined. The outcome methodology was sensitive for the outcome
of interest.
High All Outcomes: Details regarding the execution of the study protocol for outcome as-
sessment (weekly) were provided. There is no indication that there were inconsistencies
across groups for this outcome.
High All Outcomes: Final body weights were recorded for all surviving animals. Sampling
was adequate in all groups to allow for statistical analysis.
N/A All Outcomes: Blinding is not required for this outcome because it is not subjective in
nature.
Continued on next page ...
Page 83 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 1 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Nutritional/Metabolic; Nutritional/Metabolic;
Nutritional/Metabolic: Body weight; Nutritional/Metabolic: Body weight;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 20: Negative Control Response
Medium All Outcomes: The final body weights of the negative controls were reported and were
adequate. Initial body weights were not provided, so the weight gain of control animals
could not be assessed.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Medium
Low
Metric 23: Data Presentation and Analysis
High
All Outcomes: Some information to determine confounding (initial body weights) was
not provided. The study did not measure food or water intake, but this was not a dietary
or drinking water study, and these endpoints are not required for this study type accord-
ing to NTP.
Nutritional/Metabolic: The study text noted that during week 4, the two highest dose
groups were prepared incorrectly, and for the first three days of that week, the animals
were administered double the target levels. Animals in the 175 mg/kg-day group, were
instead dosed with 350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed
with 700 mg/kg-day. As a result, 2 females in each group died, and others showed ex-
cessive signs of acute toxicity (e.g., ataxia, excessive salivation, gasping, and convul-
sions). The overdose caused no deaths in males, and they showed no signs of toxicity.
The surviving animals were not dosed on the 4th day of the week to allow them to re-
cover. Dosing resumed on the 5th day. In addition to these deaths, three animals died
due to gavage error including 1 male and 1 female at 22 mg/kg-day and 1 female at 175
mg/kg-day.; Nutritional/Metabolic: The study text noted that during week 4, the two
highest dose groups were prepared incorrectly, and for the first three days of that week,
the animals were administered double the target levels. Animals in the 350 mg/kg group,
were instead dosed with 700 mg/kg, and animals in the 700 mg/kg group were dosed
with 1,400 mg/kg. No deaths occurred as a result of the dosing error, but two male mice
had convulsions and labored breathing on the third day of overdosing. Overdosed fe-
males were uncoordinated. These animals were not dosed on the 4th day of the week
to allow them to recover. Dosing resumed on the 5th day. Three males and two females
died during the study due to gavage trauma. The males were from the 175, 350, and 700
mg/kg groups, and the females were from the 175 and 300 mg/kg groups, respectively.
Nutritional/Metabolic: Some data were clearly statistically analyzed, but the statistical
methods used were not reported; the study text only specifies that the "Significance
level was set at p < 0.05)."; Nutritional/Metabolic: Some data were clearly statistically
analyzed, but the statistical methods used were not reported; the study text only specifies
that the "Significance level was set at p < 0.05)"
Continued on next page ...
Page 84 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 1 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Nutritional/Metabolic; Nutritional/Metabolic;
Nutritional/Metabolic: Body weight; Nutritional/Metabolic: Body weight;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 24: Reporting of Data
Medium Nutritional/Metabolic: Initial body weights and weekly body weight data were not pro-
vided. Only final body weights were reported as means ± SE in a table. Body weight
gain results were reported qualitatively in the text for females only, indicating that high-
dose females gained significantly more weight than controls.; Nutritional/Metabolic:
Initial body weights and weekly body weight data were not provided. Only final body
weights were reported as means ± SE in a table.
Overall Quality Determination
High
Page 85 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 2 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Renal/Kidney
Histopathology (kidney) and kidney weights
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
High The study included a concurrent negative vehicle (corn oil) control group.
N/A Positive controls are not necessary for this study type.
Medium Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Toxi-
cology Program (NTP)." The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 86 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 2 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Renal/Kidney
Histopathology (kidney) and kidney weights
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female B6C3F1 mice. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Medium Animal husbandry (caging, food and water access, temperature, humidity, and light
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that state humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was reported. NTP guidelines specify that male mice should
always be housed individually. It is unclear whether the deviations in animal husbandry
conditions had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High
High
Medium
N/A
High
Kidney weights were recorded and histopathology was conducted. The methods were
sensitive for this outcome of interest. The study did not specify whether serum chem-
istry analysis was done.
There is no indication that there were inconsistencies in the outcome assessment across
groups. Histopathology and organ weights were recorded at the end of the study.
Organ weights were measured from all surviving animals. Histopathology was con-
ducted in controls and animals from the high-dose group. This is acceptable because no
treatment-related lesions were observed.
Blinding is not necessary for initial histopathology.
A single control male had nephropathy, and lymphocytic infiltrate was observed in one
control female. There was no indication that these were unexpected or abnormal. Nega-
tive control organ weights were appropriate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium Some information to determine confounding (initial body weights) was not provided.
and Procedures The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
Continued on next page ...
Page 87 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 2 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Renal/Kidney
Histopathology (kidney) and kidney weights
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared in-
Exposure
correctly, and for the first three days of that week, the animals were administered double
the target levels. Animals in the 350 mg/kg group, were instead dosed with 700 mg/kg,
and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths occurred
as a result of the dosing error, but two male mice had convulsions and labored breathing
on the third day of overdosing. Overdosed females were uncoordinated. These animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed on
the 5th day. Three males and two females died during the study due to gavage trauma.
The males were from the 175, 350, and 700 mg/kg groups, and the females were from
the 175 and 300 mg/kg groups, respectively.
Metric 23:
Data Presentation and Analysis
Low
Statistical analysis was performed, but the methods used to analyze organ weight and
initial histopathology data weren't clearly specified, only that the significance level was
set at p < 0.05.
Metric 24:
Reporting of Data
High
Organ weights were adequately reported as means ± SEM. Kidney histopathology re-
sults were qualitatively reported in the text. Only incidences of one lesion type were
reported for high-dose animals and the controls, which allows for independent statistical
analysis.
Overall Quality Determination
High
Page 88 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 3 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Renal/Kidney; Hepatic/Liver;
Renal/Kidney: Histopathology (kidney) and kidney weights; Hepatic/Liver: Histopathology (liver) and liver weights;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High All Outcomes: The test substance was purchased from Stauffer Chemical Company. The
lot and batch number were provided.
Low All Outcomes: The purity was not reported and could not be determined on the manu-
facturer's website.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included a concurrent negative vehicle (corn oil) control
group.
All Outcomes: Positive controls are not necessary for this study type.
All Outcomes: Animals were assigned to dose groups and to cages using a random
number table. It was not specified whether animals were also normalized to starting
body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11:
Metric 12:
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
Medium All Outcomes: Fresh solutions were made every two weeks by dissolving the test mate-
rial in 100% pure corn oil. Test solutions were stored at 5 degrees C until use. Details of
mixing for homogeneity weren't provided. Testing for stability was not discussed.
High All Outcomes: Sufficient exposure administration details were reported. A consistent
gavage volume of 5 mL/kg was used. The time of day of dosing was not specified.
Medium All Outcomes: Doses were clearly reported. Dosing solutions were analyzed (method
and frequency not specified), and the text indicated that the actual concentrations admin-
istered remained within 10% of the target. Analytical values were not provided.
Medium All Outcomes: The study did not mention adherence to a specific guideline, but the text
indicated this was an NTP study. Animals were dosed 5 days per week, consistent with
the "Specifications for the Conduct of Studies to Evaluate the Toxic and Carcinogenic
Potential of Chemical, Biological and Physical Agents in Laboratory Animals for the
National Toxicology Program (NTP). The study duration was 16 weeks. The authors
did not provide justification for this duration. This is longer than a typical 90-day sub-
chronic study, and shorter than an NTP chronic/carcinogenicity study.
High All Outcomes: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 89 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 3 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Renal/Kidney; Hepatic/Liver;
Renal/Kidney: Histopathology (kidney) and kidney weights; Hepatic/Liver: Histopathology (liver) and liver weights;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium All Outcomes: The study used male and female F344/N rats. The test animal source
(Charles River Breeding Laboratories), and age purchase (5 weeks old), were reported.
Initial body weights were not specified. A quarantine period was mentioned, but the
duration was not reported.
Medium All Outcomes: Animal husbandry (caging, food and water access, temperature, humid-
ity, and light cycle) were reported. The relative humidity varied from 10% to 78% . This
deviates from NTP guidelines that stat humidity should not be below 35% or above 65%
. The temperature range in the study was 70 to 81 degrees. NTP indicates temperature
should not be above 75 degrees, and that there should be minimal fluctuations. The
number of animals per cage (n =5) was appropriate. It is unclear whether the deviations
in animal husbandry conditions had an impact on the study results.
Medium All Outcomes: The number of animals per group (10/sex) was reported and consistent
with NTP guidelines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High All Outcomes: The study included organ weights and histopathology was conducted.
The methods were sensitive for this outcome of interest.
High All Outcomes: There is no indication that there were inconsistencies in the outcome
assessment across groups. Organs were weighed and histopathology was performed at
the end of the study.
Medium All Outcomes: Histopathology was conducted in controls and animals from the 175
and 350 mg/kg-day groups. This is acceptable particularly because no treatment-related
lesions were observed. The sample size for organ weights was not provided.
N/A All Outcomes: Blinding is not necessary because the outcomes were either not subjec-
tive in nature (organ weights), or blinding is not required for initial histopathology.
Low All Outcomes: The biological responses of negative controls were not explicitly re-
ported.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Medium All Outcomes: Some information to determine confounding (initial body weights) was
not provided. The study did not measure food or water intake, but this was not a dietary
or drinking water study, and these endpoints are not required for this study type accord-
ing to NTP.
Continued on next page ...
Page 90 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 3 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Renal/Kidney; Hepatic/Liver;
Renal/Kidney: Histopathology (kidney) and kidney weights; Hepatic/Liver: Histopathology (liver) and liver weights;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
All Outcomes: The study text noted that during week 4, the two highest dose groups
Exposure
were prepared incorrectly, and for the first three days of that week, the animals were
administered double the target levels. Animals in the 175 mg/kg-day group, were instead
dosed with 350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with
700 mg/kg-day. As a result, 2 females in each group died, and others showed excessive
signs of acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The
overdose caused no deaths in males, and they showed no signs of toxicity. The surviving
animals were not dosed on the 4th day of the week to allow them to recover. Dosing
resumed on the 5th day. In addition to these deaths, three animals died due to gavage
error including 1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/kg-day.
Metric 23:
Data Presentation and Analysis
Low
All Outcomes: Statistical analysis was performed, but the methods used to analyze
initial histopathology and organ weight data weren't clearly specified, only that the
significance level was set at p < 0.05.
Metric 24:
Reporting of Data
High
All Outcomes: Negative findings for initial histopathology were reported qualitatively
in the text. Absolute and relative organ weight data were reported as means ± SE and
statistical significance was indicated.
Overall Quality Determination
High
Page 91 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 4 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Immune/Hematological
Histopathology (spleen, thymus, mesenteric lymph nodes, bone marrow); organs may have been weighed
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
High The study included a concurrent negative vehicle (corn oil) control group.
N/A Positive controls are not necessary for this study type.
Medium Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Tox-
icology Program (NTP). The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 92 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 4 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Immune/Hematological
Histopathology (spleen, thymus, mesenteric lymph nodes, bone marrow); organs may have been weighed
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female F344/N rats. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Medium Animal husbandry (caging, food and water access, temperature, humidity, and light
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that stat humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was appropriate. It is unclear whether the deviations in animal
husbandry conditions had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Outcome Assessment Methodology
Consistency of Outcome Assessment
Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High The study included thymus weights and histopathology was conducted. The methods
were sensitive for this outcome of interest.
High There is no indication that there were inconsistencies in the outcome assessment across
groups. Organs were weighed and histopathology was performed at the end of the study.
Medium Histopathology was conducted in controls and animals from the 175 and 350 mg/kg-
day groups. This is acceptable particularly because no treatment-related lesions were
observed. The sample size for organ weights was not provided.
N/A Blinding is not necessary because the outcomes were either not subjective in nature
(organ weights), or blinding is not required for initial histopathology.
Low The biological responses of negative controls were not explicitly reported.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium Some information to determine confounding (initial body weights) was not provided.
and Procedures The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
Continued on next page ...
Page 93 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 4 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Immune/Hematological
Histopathology (spleen, thymus, mesenteric lymph nodes, bone marrow); organs may have been weighed
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg-day group, were instead dosed with
350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with 700 mg/kg-
day. As a result, 2 females in each group died, and others showed excessive signs of
acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The overdose
caused no deaths in males, and they showed no signs of toxicity. The surviving animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed on
the 5th day. In addition to these deaths, three animals died due to gavage error including
1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/kg-day.
Metric 23:
Data Presentation and Analysis
Low
Statistical analysis was performed, but the methods used to analyze initial histopathol-
ogy data weren't clearly specified, only that the significance level was set at p < 0.05.
The significance for thymus weight changes was not specified, and the data were not
provided for an independent analysis.
Metric 24:
Reporting of Data
Medium
Negative findings for initial histopathology were reported qualitatively in the text. A
19% decrease in thymus weight was reported for high-dose females, relative to controls.
The significance was not specified.
Overall Quality Determination
High
Page 94 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 5 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Hepatic/Liver
Histopathology (liver) and liver weights
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
High The study included a concurrent negative vehicle (corn oil) control group.
N/A Positive controls are not necessary for this study type.
Medium Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Tox-
icology Program (NTP). The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 95 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 5 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Hepatic/Liver
Histopathology (liver) and liver weights
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female B6C3F1 mice. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Medium Animal husbandry (caging, food and water access, temperature, humidity, and light
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that state humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was reported. NTP guidelines specify that male mice should
always be housed individually. It is unclear whether the deviations in animal husbandry
conditions had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High
High
Medium
N/A
Medium
Liver weights were recorded and histopathology was conducted. The methods were sen-
sitive for this outcome of interest. The study did not specify whether serum chemistry
analysis was done.
There is no indication that there were inconsistencies in the outcome assessment across
groups. Histopathology and organ weights were recorded at the end of the study.
Organ weights were measured from all surviving animals. Histopathology was con-
ducted in controls and animals from the high-dose group. This is acceptable because no
treatment-related lesions were observed.
Blinding is not necessary for initial histopathology.
The biological responses of negative controls were not explicitly reported for
histopathology; negative findings were qualitatively reported in the text. Negative con-
trol organ weights were appropriate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium Some information to determine confounding (initial body weights) was not provided.
and Procedures The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
Continued on next page ...
Page 96 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 5 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Hepatic/Liver
Histopathology (liver) and liver weights
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared in-
Exposure
correctly, and for the first three days of that week, the animals were administered double
the target levels. Animals in the 350 mg/kg group, were instead dosed with 700 mg/kg,
and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths occurred
as a result of the dosing error, but two male mice had convulsions and labored breathing
on the third day of overdosing. Overdosed females were uncoordinated. These animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed on
the 5th day. Three males and two females died during the study due to gavage trauma.
The males were from the 175, 350, and 700 mg/kg groups, and the females were from
the 175 and 300 mg/kg groups, respectively.
Metric 23:
Data Presentation and Analysis
Low
Statistical analysis was performed, but the methods used to analyze organ weight and
initial histopathology data weren't clearly specified, only that the significance level was
set at p < 0.05.
Metric 24:
Reporting of Data
High
Organ weights were adequately reported as means ± SEM. Negative findings for initial
histopathology were reported qualitatively in the text.
Overall Quality Determination
High
Page 97 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 6 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Neurological/Behavioral
Serum cholinesterase, necropsy (including brain weight), brain histopathology
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls High
Positive Controls N/A
Randomized Allocation of Animals Medium
The study included a concurrent negative vehicle (corn oil) control group.
Positive controls are not necessary for this study type.
Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Toxi-
cology Program (NTP)." The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 98 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 6 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Neurological/Behavioral
Serum cholinesterase, necropsy (including brain weight), brain histopathology
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female B6C3F1 mice. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Medium Animal husbandry (caging, food and water access, temperature, humidity, and light
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that state humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was reported. NTP guidelines specify that male mice should
always be housed individually. It is unclear whether the deviations in animal husbandry
conditions had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Low Brains were weighed. Histopathology was measured in controls and high-dose mice.
What animals were microscopically examined and when is unclear. Some animals died
due to gavage trauma, and it was not specified whether these animals were examined for
histopathology. Additionally, animals in this study were dosed 5 days per week for 16
weeks, yet histopathology images shown in the study indicate they are from rats treated
for 90 days (so it is not clear whether this would also be true for mice). Five days per
week for 16 weeks would be 80 days. The study also indicated that serum cholinesterase
levels were measured and referenced: Ellman, G.L., Courtney, K.D., Andres, V., Jr.,
and Featherstone, R.M. (1961). A new and rapid colorimetric determination of acetyl-
cholinesterase activity. Biochem. Phamacol. 7,88-95 for methods. Overall, the methods
were sensitive for the outcomes of interest, but there were limitations in reporting the
details.
Medium Details regarding the execution of the study protocols for outcome assessment were
partially reported. The time of serum draw for measuring cholinesterase activity wasn't
specified. The timing of histopathological examinations is unclear (90 days vs. after 16
weeks). Ogan weights were presumably measured at necropsy.
Low Results for serum cholinesterase were qualitatively reported and the sample size was not
specified either in the methods or in the results. Based on the "n's" provided text. It is
unclear whether brain tissue was examined for animals from all groups. The results for
brain were only reported for rats. Organ weight data for this organ were not reported.
High Secondary histopathological analyses were conducted in a blind manner. Blinding is not
necessary for organ weights or initial histopathology.
Continued on next page ...
Page 99 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 6 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Neurological/Behavioral
Serum cholinesterase, necropsy (including brain weight), brain histopathology
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 20: Negative Control Response
Low The biological responses of the negative controls were not provided (qualitatively or
quantitatively) so the adequacy cannot be determined.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Medium
Low
Metric 23: Data Presentation and Analysis
Low
Metric 24: Reporting of Data
Low
Some information to determine confounding (initial body weights) was not provided.
The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
The study text noted that during week 4, the two highest dose groups were prepared
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 350 mg/kg group, were instead dosed with 700
mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths
occurred as a result of the dosing error, but two male mice had convulsions and labored
breathing on the third day of overdosing. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 300 mg/kg groups,
respectively.
Statistical methods used to analyze brain lesion data were adequately described and
significance was reported in the results. It is unclear, however, whether it was appro-
priate to include animals that died early due to gavage trauma in the statistical analysis.
The methods used to analyze cholinesterase activity or organ weights weren't clearly
specified, only that the significance level was set at p < 0.05. However, the statistical
significance of brain weight changes was not specified and the data were not available
for an independent review.
Negative findings for serum cholinesterase activity were qualitatively reported in the
text. Histopathology results were not reported in table form. No brain lesions were
reported for mice. Other dose groups were not mentioned. No results for brain weight
were reported so it is assumed there were no changes.
Overall Quality Determination
Medium
Page 100 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 7 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Neurological/Behavioral
Serum cholinesterase, necropsy (including brain weight), brain histopathology
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls High
Positive Controls N/A
Randomized Allocation of Animals Medium
The study included a concurrent negative vehicle (corn oil) control group.
Positive controls are not necessary for this study type.
Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Tox-
icology Program (NTP). The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 101 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 7 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Neurological/Behavioral
Serum cholinesterase, necropsy (including brain weight), brain histopathology
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female F344/N rats. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Medium Animal husbandry (caging, food and water access, temperature, humidity, and light
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that stat humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was appropriate. It is unclear whether the deviations in animal
husbandry conditions had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Low Brains were weighed. Initial histopathology was performed on the brain, followed by a
more detailed histopathological analysis to quantitate the damage observed. What an-
imals were microscopically examined and when is unclear. Some animals died early
in the study due to overdose, and other animals died due to gavage trauma. It was not
specified whether these animals were examined, but based in the incidences reported
(which are all out of an n of 10/sex), it appears that they were. Additionally, animals in
this study were dosed 5 days per week for 16 weeks, yet histopathology images shown
in the study indicate they are from rats treated for 90 days. Five days per week for 16
weeks would be 80 days. The study also indicated that serum cholinesterase levels were
measured and referenced: Ellman, G.L., Courtney, K.D., Andres, V., Jr., and Feather-
stone, R.M. (1961). A new and rapid colorimetric determination of acetylcholinesterase
activity. Biochem. Phamacol. 7,88-95 for methods. Overall, the methods were sensitive
for the outcomes of interest, but there were limitations in reporting the details.
Medium Details regarding the execution of the study protocols for outcome assessment were
partially reported. The time of serum draw for measuring cholinesterase activity wasn't
specified. The timing of histopathological examinations is unclear (90 days vs. after 16
weeks). Ogan weights were presumably measured at necropsy.
Medium Results for serum cholinesterase were qualitatively reported and the sample size was
not specified either in the methods or in the results. Based on the "n.s" provided text,
it appears that all animals from all dose groups were microscopically examined. The
sample size for organ weight measurements was not reported.
High Secondary histopathological analyses were conducted in a blind manner. Blinding is not
necessary for organ weights or initial histopathology.
Continued on next page ...
Page 102 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 7 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Neurological/Behavioral
Serum cholinesterase, necropsy (including brain weight), brain histopathology
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 20: Negative Control Response
Low The biological responses of the negative controls were not provided (qualitatively or
quantitatively) so the adequacy cannot be determined.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium Some information to determine confounding (initial body weights) was not provided.
and Procedures The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
Metric 22: Health Outcomes Unrelated to Low The study text noted that during week 4, the two highest dose groups were prepared
Exposure incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg-day group, were instead dosed with
350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with 700 mg/kg-
day. As a result, 2 females in each group died, and others showed excessive signs of
acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The overdose
caused no deaths in males, and they showed no signs of toxicity. The surviving animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed on
the 5th day. In addition to these deaths, three animals died due to gavage error including
1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/kg-day.
Metric 23: Data Presentation and Analysis Low Statistical methods used to analyze brain lesion data were adequately described and
significance was reported in the results. It is unclear, however, whether it was appro-
priate to include animals that died during week 4 due to the overdose, or animals that
died early due to gavage trauma in the statistical analysis. The methods used to analyze
cholinesterase activity or organ weights weren't clearly specified, only that the signif-
icance level was set at p < 0.05. However, the statistical significance of brain weight
changes was not specified and the data were not available for an independent review.
Metric 24: Reporting of Data Low Serum cholinesterase data were qualitatively reported in the text. Histopathology results
were not reported in table form. The incidences of brain lesions were reported for the
two highest-dose groups in females, and for the high-dose group in males. Other dose
groups were not mentioned; no lesions were observed in controls. An increase in sever-
ity with dose was mentioned. Representative images were shown, although the figure
legends reporting the duration of dosing stated that the images were from animals dosed
for 90 days. The study reported an 11% decrease in brain weight in high-dose females.
It was not specified whether this was absolute or relative brain weight, and statistical
significance was not specified.
Overall Quality Determination Medium
Page 103 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 8 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Mortality
Survival
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
High The study included a concurrent negative vehicle (corn oil) control group.
N/A Positive controls are not necessary for this study type.
Medium Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Tox-
icology Program (NTP). The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 104 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 8 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Mortality
Survival
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female B6C3F1 mice. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Medium Animal husbandry (caging, food and water access, temperature, humidity, and light
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that state humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was reported. NTP guidelines specify that male mice should
always be housed individually. It is unclear whether the deviations in animal husbandry
conditions had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology Medium
Metric 17: Consistency of Outcome Assessment High
Metric 18: Sampling Adequacy High
Metric 19: Blinding of Assessors N/A
Metric 20: Negative Control Response High
The study clearly recorded any animal deaths, but the frequency of observations for the
mortality endpoint was not specified in the study methods. This is not expected to have
an impact on the study results.
A protocol for outcome assessment was not provided, but the survival of animals until
termination was recorded for all groups. There is no indication that there were inconsis-
tencies across groups for this outcome.
All animals were sampled and accounted for.
Blinding is not required for this outcome because it is not subjective in nature.
No control animals died.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium Some information to determine confounding (initial body weights) was not provided.
and Procedures The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
Continued on next page ...
Page 105 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 8 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Mortality
Survival
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Low The study text noted that during week 4, the two highest dose groups were prepared in-
correctly, and for the first three days of that week, the animals were administered double
the target levels. Animals in the 350 mg/kg group, were instead dosed with 700 mg/kg,
and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths occurred
as a result of the dosing error, but two male mice had convulsions and labored breathing
on the third day of overdosing. Overdosed females were uncoordinated. These animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed on
the 5th day. Three males and two females died during the study due to gavage trauma.
The males were from the 175, 350, and 700 mg/kg groups, and the females were from
the 175 and 300 mg/kg groups, respectively.
N/A All of the deaths were due to gavage-related deaths, statistical analysis was not neces-
sary.
High Mortality incidences were clearly reported and the cause of death was indicated.
Overall Quality Determination
High
Page 106 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 9 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Mortality
Survival
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
High The study included a concurrent negative vehicle (corn oil) control group.
N/A Positive controls are not necessary for this study type.
Medium Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Tox-
icology Program (NTP). The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 107 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 9 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Mortality
Survival
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female F344/N rats. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Medium Animal husbandry (caging, food and water access, temperature, humidity, and light
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that stat humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was appropriate. It is unclear whether the deviations in animal
husbandry conditions had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology Medium
Metric 17: Consistency of Outcome Assessment High
Metric 18: Sampling Adequacy High
Metric 19: Blinding of Assessors N/A
Metric 20: Negative Control Response High
The study clearly recorded any animal deaths, but the frequency of observations for the
mortality endpoint was not specified in the study methods. This is not expected to have
an impact on the study results.
A protocol for outcome assessment was not provided, but the survival of animals until
termination was recorded for all groups. There is no indication that there were inconsis-
tencies across groups for this outcome.
All animals were sampled.
Blinding is not required for this outcome because it is not subjective in nature.
No control animals died.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium Some information to determine confounding (initial body weights) was not provided.
and Procedures The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
Continued on next page ...
Page 108 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 9 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Mortality
Survival
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg-day group, were instead dosed with
350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with 700 mg/kg-
day. As a result, 2 females in each group died, and others showed excessive signs of
acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The overdose
caused no deaths in males, and they showed no signs of toxicity. The surviving animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed on
the 5th day. In addition to these deaths, three animals died due to gavage error including
1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/kg-day.
Metric 23:
Data Presentation and Analysis
High
Some data were clearly statistically analyzed, but the statistical methods used were not
reported; only p-values were provided in the data tables. It does not appear that the
mortality data were statistically analyzed, but the majority of deaths were related to an
overdose or to gavage trauma. Incidences were provided to allow for an independent
analysis.
Metric 24:
Reporting of Data
Medium
Mortality incidences were clearly reported. For the few animals whose deaths were
treatment-related, the timing and causes of death were not reported.
Overall Quality Determination
High
Page 109 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 10 of 15
Study Citation: Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Health Lung/Respiratory; Gastrointestinal; Thyroid; Endocrine; Cardiovascular;
Outcome(s):
Reported Health Lung/Respiratory; Histopathology lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs
Effect(s): may have been weighed; Thyroid: Histopathology (thyroid); thyroid may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands
may have been weighed; Cardiovascular: Histopathology (heart); heart may have been weighed;
Duration: Chronic (>91 days) 16 weeks - Rats and Mice
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High All Outcomes: The test substance was purchased from Stauffer Chemical Company. The
lot and batch number were provided.
Low All Outcomes: The purity was not reported and could not be determined on the manu-
facturer's website.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included a concurrent negative vehicle (corn oil) control
group.
All Outcomes: Positive controls are not necessary for this study type.
All Outcomes: Animals were assigned to dose groups and to cages using a random
number table. It was not specified whether animals were also normalized to starting
body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11:
Metric 12:
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
Medium All Outcomes: Fresh solutions were made every two weeks by dissolving the test mate-
rial in 100% pure corn oil. Test solutions were stored at 5 degrees C until use. Details of
mixing for homogeneity weren't provided. Testing for stability was not discussed.
High All Outcomes: Sufficient exposure administration details were reported. A consistent
gavage volume of 5 mL/kg was used. The time of day of dosing was not specified.
Medium All Outcomes: Doses were clearly reported. Dosing solutions were analyzed (method
and frequency not specified), and the text indicated that the actual concentrations admin-
istered remained within 10% of the target. Analytical values were not provided.
Medium All Outcomes: The study did not mention adherence to a specific guideline, but the text
indicated this was an NTP study. Animals were dosed 5 days per week, consistent with
the "Specifications for the Conduct of Studies to Evaluate the Toxic and Carcinogenic
Potential of Chemical, Biological and Physical Agents in Laboratory Animals for the
National Toxicology Program (NTP). The study duration was 16 weeks. The authors
did not provide justification for this duration. This is longer than a typical 90-day sub-
chronic study, and shorter than an NTP chronic/carcinogenicity study.
High All Outcomes: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Continued on next page ...
Page 110 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 10 of 15
... continued from previous page
Study Citation: Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Health Lung/Respiratory; Gastrointestinal; Thyroid; Endocrine; Cardiovascular;
Outcome(s):
Reported Health Lung/Respiratory; Histopathology lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs
Effect(s): may have been weighed; Thyroid: Histopathology (thyroid); thyroid may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands
may have been weighed; Cardiovascular: Histopathology (heart); heart may have been weighed;
Duration: Chronic (>91 days) 16 weeks - Rats and Mice
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469641
Domain
Metric
Rating
Comments
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Metric 14:
Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium Lung/Respiratory: The study used male and female F344/N rats. The test animal source
(Charles River Breeding Laboratories), and age purchase (5 weeks old), were reported.
Initial body weights were not specified. A quarantine period was mentioned, but the
duration was not reported.; Gastrointestinal: The study used male and female F344/N
rats. The test animal source (Charles River Breeding Laboratories), and age purchase
(5 weeks old), were reported. Initial body weights were not specified. A quarantine
period was mentioned, but the duration was not reported.; Thyroid: The study used male
and female F344/N rats. The test animal source (Charles River Breeding Laboratories),
and age purchase (5 weeks old), were reported. Initial body weights were not specified.
A quarantine period was mentioned, but the duration was not reported.; Endocrine:
The study used male and female F344/N rats. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.; Cardiovascular: The study used male and female B6C3F1 mice. The
test animal source (Charles River Breeding Laboratories), and age purchase (5 weeks
old), were reported. Initial body weights were not specified. A quarantine period was
mentioned, but the duration was not reported.
Medium All Outcomes: Animal husbandry (caging, food and water access, temperature, humid-
ity, and light cycle) were reported. The relative humidity varied from 10% to 78% . This
deviates from NTP guidelines that stat humidity should not be below 35% or above 65%
. The temperature range in the study was 70 to 81 degrees. NTP indicates temperature
should not be above 75 degrees, and that there should be minimal fluctuations. The
number of animals per cage (n =5) was appropriate. It is unclear whether the deviations
in animal husbandry conditions had an impact on the study results.
Medium All Outcomes: The number of animals per group (10/sex) was reported and consistent
with NTP guidelines.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Outcome Assessment Methodology Medium
Consistency of Outcome Assessment High
Sampling Adequacy High
All Outcomes: The methods did not specify which organs were weighed. Histopathol-
ogy was conducted which is considered to be a sensitive method for this outcome of
interest.
All Outcomes: There is no indication that there were inconsistencies in the outcome
assessment across groups. Histopathology was performed at the end of the study.
All Outcomes: Histopathology was conducted in controls and animals from the 175
and 350 mg/kg-day groups. This is acceptable particularly because no treatment-related
lesions were observed.
Continued on next page ...
Page 111 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 10 of 15
Domain
... continued from previous page
Study Citation: Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Health Lung/Respiratory; Gastrointestinal; Thyroid; Endocrine; Cardiovascular;
Outcome(s):
Reported Health Lung/Respiratory; Histopathology lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs
Effect(s): may have been weighed; Thyroid: Histopathology (thyroid); thyroid may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands
may have been weighed; Cardiovascular: Histopathology (heart); heart may have been weighed;
Duration: Chronic (>91 days) 16 weeks - Rats and Mice
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469641
Metric
Rating
Comments
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
N/A All Outcomes: Blinding is not necessary for initial histopathology.
Medium All Outcomes: The biological responses of negative controls were not explicitly re-
ported; negative findings were qualitatively reported in the text.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium All Outcomes: Some information to determine confounding (initial body weights) was
and Procedures not provided. The study did not measure food or water intake, but this was not a dietary
or drinking water study, and these endpoints are not required for this study type accord-
ing to NTP.
Continued on next page ...
Page 112 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 10 of 15
... continued from previous page
Study Citation: Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Health Lung/Respiratory; Gastrointestinal; Thyroid; Endocrine; Cardiovascular;
Outcome(s):
Reported Health Lung/Respiratory; Histopathology lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs
Effect(s): may have been weighed; Thyroid: Histopathology (thyroid); thyroid may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands
may have been weighed; Cardiovascular: Histopathology (heart); heart may have been weighed;
Duration: Chronic (>91 days) 16 weeks - Rats and Mice
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469641
Domain
Metric
Rating
Comments
Metric 22: Health Outcomes Unrelated to
Exposure
Low Lung/Respiratory: The study text noted that during week 4, the two highest dose groups
were prepared incorrectly, and for the first three days of that week, the animals were
administered double the target levels. Animals in the 175 mg/kg-day group, were instead
dosed with 350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with
700 mg/kg-day. As a result, 2 females in each group died, and others showed excessive
signs of acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The
overdose caused no deaths in males, and they showed no signs of toxicity. The surviving
animals were not dosed on the 4th day of the week to allow them to recover. Dosing
resumed on the 5th day. In addition to these deaths, three animals died due to gavage
error including 1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/kg-day.;
Gastrointestinal: The study text noted that during week 4, the two highest dose groups
were prepared incorrectly, and for the first three days of that week, the animals were
administered double the target levels. Animals in the 175 mg/kg-day group, were instead
dosed with 350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with
700 mg/kg-day. As a result, 2 females in each group died, and others showed excessive
signs of acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions).
The overdose caused no deaths in males, and they showed no signs of toxicity. The
surviving animals were not dosed on the 4th day of the week to allow them to recover.
Dosing resumed on the 5th day. In addition to these deaths, three animals died due to
gavage error including 1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/
kg-day.; Thyroid: The study text noted that during week 4, the two highest dose groups
were prepared incorrectly, and for the first three days of that week, the animals were
administered double the target levels. Animals in the 175 mg/kg-day group, were instead
dosed with 350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with
700 mg/kg-day. As a result, 2 females in each group died, and others showed excessive
signs of acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The
overdose caused no deaths in males, and they showed no signs of toxicity. The surviving
animals were not dosed on the 4th day of the week to allow them to recover. Dosing
resumed on the 5th day. In addition to these deaths, three animals died due to gavage
error including 1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/kg-day.
Continued on next page ...
Page 113 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 10 of 15
... continued from previous page
Study Citation: Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Health Lung/Respiratory; Gastrointestinal; Thyroid; Endocrine; Cardiovascular;
Outcome(s):
Reported Health Lung/Respiratory; Histopathology lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs
Effect(s): may have been weighed; Thyroid: Histopathology (thyroid); thyroid may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands
may have been weighed; Cardiovascular: Histopathology (heart); heart may have been weighed;
Duration: Chronic (>91 days) 16 weeks - Rats and Mice
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469641
Domain
Metric
Rating
Comments
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Low Continued, metric comment- Endocrine: The study text noted that during week 4, the
two highest dose groups were prepared incorrectly, and for the first three days of that
week, the animals were administered double the target levels. Animals in the 175 mg/
kg-day group, were instead dosed with 350 mg/kg-day, and animals in the 350 mg/kg-
day group were dosed with 700 mg/kg-day. As a result, 2 females in each group died,
and others showed excessive signs of acute toxicity (e.g., ataxia, excessive salivation,
gasping, and convulsions). The overdose caused no deaths in males, and they showed
no signs of toxicity. The surviving animals were not dosed on the 4th day of the week
to allow them to recover. Dosing resumed on the 5th day. In addition to these deaths,
three animals died due to gavage error including 1 male and 1 female at 22 mg/kg-day
and 1 female at 175 mg/kg-day.; Cardiovascular: The study text noted that during week
4, the two highest dose groups were prepared incorrectly, and for the first three days of
that week, the animals were administered double the target levels. Animals in the 350
mg/kg group, were instead dosed with 700 mg/kg, and animals in the 700 mg/kg group
were dosed with 1,400 mg/kg. No deaths occurred as a result of the dosing error, but
two male mice had convulsions and labored breathing on the third day of overdosing.
Overdosed females were uncoordinated. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 300 mg/kg groups,
respectively.
Low All Outcomes: Statistical analysis was performed, but the methods used to analyze
initial histopathology data weren't clearly specified, only that the significance level was
set at p < 0.05.
High All Outcomes: Negative findings for initial histopathology were reported qualitatively in
the text.
Overall Quality Determination
High
Page 114 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 11 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Cardiovascular; Endocrine; Gastrointestinal; Lung/Respiratory; Gastrointestinal; Thyroid; Immune/Hematological;
Cardiovascular: Histopathology (heart); heart may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands may have been
weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Lung/Respiratory: Histopathology
lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Thyroid:
Histopathology (thyroid); thyroid may have been weighed; Immune/Hematological: Histopathology (spleen, thymus, mesenteric lymph nodes, bone
marrow); organs may have been weighed;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High All Outcomes: The test substance was purchased from Stauffer Chemical Company. The
lot and batch number were provided.
Low All Outcomes: The purity was not reported and could not be determined on the manu-
facturer's website.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included a concurrent negative vehicle (corn oil) control
group.
All Outcomes: Positive controls are not necessary for this study type.
All Outcomes: Animals were assigned to dose groups and to cages using a random
number table. It was not specified whether animals were also normalized to starting
body weights.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test Medium
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations Medium
All Outcomes: Fresh solutions were made every two weeks by dissolving the test mate-
rial in 100% pure corn oil. Test solutions were stored at 5 degrees C until use. Details of
mixing for homogeneity weren't provided. Testing for stability was not discussed.
All Outcomes: Sufficient exposure administration details were reported. A consistent
gavage volume of 5 mL/kg was used. The time of day of dosing was not specified.
All Outcomes: Doses were clearly reported. Dosing solutions were analyzed (method
and frequency not specified), and the text indicated that the actual concentrations admin-
istered remained within 10% of the target. Analytical values were not provided.
Continued on next page ...
Page 115 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 11 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Cardiovascular; Endocrine; Gastrointestinal; Lung/Respiratory; Gastrointestinal; Thyroid; Immune/Hematological;
Cardiovascular: Histopathology (heart); heart may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands may have been
weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Lung/Respiratory: Histopathology
lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Thyroid:
Histopathology (thyroid); thyroid may have been weighed; Immune/Hematological: Histopathology (spleen, thymus, mesenteric lymph nodes, bone
marrow); organs may have been weighed;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 10: Exposure Frequency and Duration
Medium Cardiovascular: The study did not mention adherence to a specific guideline, but the text
indicated this was an NTP study. Animals were dosed 5 days per week, consistent with
the "Specifications for the Conduct of Studies to Evaluate the Toxic and Carcinogenic
Potential of Chemical, Biological and Physical Agents in Laboratory Animals for the
National Toxicology Program (NTP). The study duration was 16 weeks. The authors
did not provide justification for this duration. This is longer than a typical 90-day sub-
chronic study, and shorter than an NTP chronic/carcinogenicity study.; Endocrine: The
study did not mention adherence to a specific guideline, but the text indicated this was
an NTP study. Animals were dosed 5 days per week, consistent with the "Specifications
for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of Chemi-
cal, Biological and Physical Agents in Laboratory Animals for the National Toxicology
Program (NTP). The study duration was 16 weeks. The authors did not provide justifica-
tion for this duration. This is longer than a typical 90-day subchronic study, and shorter
than an NTP chronic/carcinogenicity study.; Gastrointestinal: The study did not mention
adherence to a specific guideline, but the text indicated this was an NTP study. Ani-
mals were dosed 5 days per week, consistent with the "Specifications for the Conduct of
Studies to Evaluate the Toxic and Carcinogenic Potential of Chemical, Biological and
Physical Agents in Laboratory Animals for the National Toxicology Program (NTP)."
The study duration was 16 weeks. The authors did not provide justification for this du-
ration. This is longer than a typical 90-day subchronic study, and shorter than an NTP
chronic/carcinogenicity study.; Lung/Respiratory: The study did not mention adherence
to a specific guideline, but the text indicated this was an NTP study. Animals were dosed
5 days per week, consistent with the "Specifications for the Conduct of Studies to Eval-
uate the Toxic and Carcinogenic Potential of Chemical, Biological and Physical Agents
in Laboratory Animals for the National Toxicology Program (NTP). The study duration
was 16 weeks. The authors did not provide justification for this duration. This is longer
than a typical 90-day subchronic study, and shorter than an NTP chronic/carcinogenicity
study.; Gastrointestinal: The study did not mention adherence to a specific guideline,
but the text indicated this was an NTP study. Animals were dosed 5 days per week, con-
sistent with the "Specifications for the Conduct of Studies to Evaluate the Toxic and
Carcinogenic Potential of Chemical, Biological and Physical Agents in Laboratory An-
imals for the National Toxicology Program (NTP). The study duration was 16 weeks.
The authors did not provide justification for this duration. This is longer than a typical
90-day subchronic study, and shorter than an NTP chronic/carcinogenicity study.
Continued on next page ...
Page 116 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 11 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Cardiovascular; Endocrine; Gastrointestinal; Lung/Respiratory; Gastrointestinal; Thyroid; Immune/Hematological;
Cardiovascular: Histopathology (heart); heart may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands may have been
weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Lung/Respiratory: Histopathology
lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Thyroid:
Histopathology (thyroid); thyroid may have been weighed; Immune/Hematological: Histopathology (spleen, thymus, mesenteric lymph nodes, bone
marrow); organs may have been weighed;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Continued metric comment- Thyroid: The study did not mention adherence to a spe-
cific guideline, but the text indicated this was an NTP study. Animals were dosed 5 days
per week, consistent with the "Specifications for the Conduct of Studies to Evaluate the
Toxic and Carcinogenic Potential of Chemical, Biological and Physical Agents in Lab-
oratory Animals for the National Toxicology Program (NTP). The study duration was
16 weeks. The authors did not provide justification for this duration. This is longer than
a typical 90-day subchronic study, and shorter than an NTP chronic/carcinogenicity
study.; Immune/Hematological: The study did not mention adherence to a specific
guideline, but the text indicated this was an NTP study. Animals were dosed 5 days
per week, consistent with the "Specifications for the Conduct of Studies to Evaluate the
Toxic and Carcinogenic Potential of Chemical, Biological and Physical Agents in Labo-
ratory Animals for the National Toxicology Program (NTP)." The study duration was 16
weeks. The authors did not provide justification for this duration. This is longer than a
typical 90-day subchronic study, and shorter than an NTP chronic/carcinogenicity study.
High Cardiovascular: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values;
Endocrine: The study tested 5 dose groups plus a control. This is consistent with NTP
guidelines. The spacing was sufficient to identify NOAEL and LOAEL values; Gas-
trointestinal: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values.;
Lung/Respiratory: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values;
Gastrointestinal: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values.;
Thyroid: The study tested 5 dose groups plus a control. This is consistent with NTP
guidelines. The spacing was sufficient to identify NOAEL and LOAEL values; Immune/
Hematological: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values.
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 117 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 11 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Cardiovascular; Endocrine; Gastrointestinal; Lung/Respiratory; Gastrointestinal; Thyroid; Immune/Hematological;
Cardiovascular: Histopathology (heart); heart may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands may have been
weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Lung/Respiratory: Histopathology
lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Thyroid:
Histopathology (thyroid); thyroid may have been weighed; Immune/Hematological: Histopathology (spleen, thymus, mesenteric lymph nodes, bone
marrow); organs may have been weighed;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13:
Test Animal Characteristics
Metric 14:
Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium Cardiovascular: The study used male and female F344/N rats. The test animal source
(Charles River Breeding Laboratories), and age purchase (5 weeks old), were reported.
Initial body weights were not specified. A quarantine period was mentioned, but the
duration was not reported.; Endocrine: The study used male and female B6C3F1 mice.
The test animal source (Charles River Breeding Laboratories), and age purchase (5
weeks old), were reported. Initial body weights were not specified. A quarantine period
was mentioned, but the duration was not reported.; Gastrointestinal: The study used
male and female B6C3F1 mice. The test animal source (Charles River Breeding Lab-
oratories), and age purchase (5 weeks old), were reported. Initial body weights were
not specified. A quarantine period was mentioned, but the duration was not reported.;
Lung/Respiratory: The study used male and female B6C3F1 mice. The test animal
source (Charles River Breeding Laboratories), and age purchase (5 weeks old), were
reported. Initial body weights were not specified. A quarantine period was mentioned,
but the duration was not reported.; Gastrointestinal: The study used male and female
B6C3F1 mice. The test animal source (Charles River Breeding Laboratories), and age
purchase (5 weeks old), were reported. Initial body weights were not specified. A quar-
antine period was mentioned, but the duration was not reported.; Thyroid: The study
used male and female B6C3F1 mice. The test animal source (Charles River Breeding
Laboratories), and age purchase (5 weeks old), were reported. Initial body weights were
not specified. A quarantine period was mentioned, but the duration was not reported.;
Immune/Hematological: The study used male and female B6C3F1 mice. The test animal
source (Charles River Breeding Laboratories), and age purchase (5 weeks old), were
reported. Initial body weights were not specified. A quarantine period was mentioned,
but the duration was not reported.
Medium All Outcomes: Animal husbandry (caging, food and water access, temperature, humid-
ity, and light cycle) were reported. The relative humidity varied from 10% to 78% . This
deviates from NTP guidelines that state humidity should not be below 35% or above
65% . The temperature range in the study was 70 to 81 degrees. NTP indicates tempera-
ture should not be above 75 degrees, and that there should be minimal fluctuations. The
number of animals per cage (n =5) was reported. NTP guidelines specify that male mice
should always be housed individually. It is unclear whether the deviations in animal
husbandry conditions had an impact on the study results.
Medium All Outcomes: The number of animals per group (10/sex) was reported and consistent
with NTP guidelines.
Domain 5: Outcome Assessment
Continued on next page .
Page 118 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 11 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Cardiovascular; Endocrine; Gastrointestinal; Lung/Respiratory; Gastrointestinal; Thyroid; Immune/Hematological;
Cardiovascular: Histopathology (heart); heart may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands may have been
weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Lung/Respiratory: Histopathology
lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Thyroid:
Histopathology (thyroid); thyroid may have been weighed; Immune/Hematological: Histopathology (spleen, thymus, mesenteric lymph nodes, bone
marrow); organs may have been weighed;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric
16:
Metric
17:
Metric
18:
Metric
19:
Metric
20:
Metric 16: Outcome Assessment Methodology
Consistency of Outcome Assessment
Sampling Adequacy
Blinding of Assessors
Negative Control Response
Medium
High
Medium
N/A
Medium
All Outcomes: The methods did not specify which organs were weighed. Histopathol-
ogy was conducted which is considered to be a sensitive method for this outcome of
interest.
All Outcomes: There is no indication that there were inconsistencies in the outcome
assessment across groups. Histopathology was performed at the end of the study.
All Outcomes: Histopathology was conducted in controls and animals from the high-
dose group. This is acceptable because no treatment-related lesions were observed.
All Outcomes: Blinding is not necessary for initial histopathology.
All Outcomes: The biological responses of negative controls were not explicitly re-
ported; negative findings were qualitatively reported in the text.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium All Outcomes: Some information to determine confounding (initial body weights) was
and Procedures not provided. The study did not measure food or water intake, but this was not a dietary
or drinking water study, and these endpoints are not required for this study type accord-
ing to NTP.
Continued on next page ...
Page 119 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 5469641 Table: 11 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Cardiovascular; Endocrine; Gastrointestinal; Lung/Respiratory; Gastrointestinal; Thyroid; Immune/Hematological;
Cardiovascular: Histopathology (heart); heart may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands may have been
weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Lung/Respiratory: Histopathology
lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Thyroid:
Histopathology (thyroid); thyroid may have been weighed; Immune/Hematological: Histopathology (spleen, thymus, mesenteric lymph nodes, bone
marrow); organs may have been weighed;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain Metric Rating Comments
Metric 22: Health Outcomes Unrelated to Low Cardiovascular: The study text noted that during week 4, the two highest dose groups
Exposure were prepared incorrectly, and for the first three days of that week, the animals were ad-
ministered double the target levels. Animals in the 175 mg/kg-day group, were instead
dosed with 350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with
700 mg/kg-day. As a result, 2 females in each group died, and others showed excessive
signs of acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The
overdose caused no deaths in males, and they showed no signs of toxicity. The surviv-
ing animals were not dosed on the 4th day of the week to allow them to recover. Dosing
resumed on the 5th day. In addition to these deaths, three animals died due to gavage
error including 1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/kg-day.;
Endocrine: The study text noted that during week 4, the two highest dose groups were
prepared incorrectly, and for the first three days of that week, the animals were admin-
istered double the target levels. Animals in the 350 mg/kg group, were instead dosed
with 700 mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg.
No deaths occurred as a result of the dosing error, but two male mice had convulsions
and labored breathing on the third day of overdosing. Overdosed females were unco-
ordinated. These animals were not dosed on the 4th day of the week to allow them to
recover. Dosing resumed on the 5th day. Three males and two females died during the
study due to gavage trauma. The males were from the 175, 350, and 700 mg/kg groups,
and the females were from the 175 and 300 mg/kg groups, respectively.; Gastrointesti-
nal: The study text noted that during week 4, the two highest dose groups were prepared
incorrectly, and for the first three days of that week, the animals were administered dou-
ble the target levels. Animals in the 350 mg/kg group, were instead dosed with 700 mg/
kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths oc-
curred as a result of the dosing error, but two male mice had convulsions and labored
breathing on the third day of overdosing. Overdosed females were uncoordinated. These
animals were not dosed on the 4th day of the week to allow them to recover. Dosing re-
sumed on the 5th day. Three males and two females died during the study due to gavage
trauma. The males were from the 175, 350, and 700 mg/kg groups, and the females were
from the 175 and 300 mg/kg groups, respectively.
Continued on next page ...
Page 120 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 11 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Cardiovascular; Endocrine; Gastrointestinal; Lung/Respiratory; Gastrointestinal; Thyroid; Immune/Hematological;
Cardiovascular: Histopathology (heart); heart may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands may have been
weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Lung/Respiratory: Histopathology
lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Thyroid:
Histopathology (thyroid); thyroid may have been weighed; Immune/Hematological: Histopathology (spleen, thymus, mesenteric lymph nodes, bone
marrow); organs may have been weighed;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22: Health Outcomes Unrelated to
Exposure
Low Continued metric comment- Lung/Respiratory: The study text noted that during week
4, the two highest dose groups were prepared incorrectly, and for the first three days of
that week, the animals were administered double the target levels. Animals in the 350
mg/kg group, were instead dosed with 700 mg/kg, and animals in the 700 mg/kg group
were dosed with 1,400 mg/kg. No deaths occurred as a result of the dosing error, but
two male mice had convulsions and labored breathing on the third day of overdosing.
Overdosed females were uncoordinated. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 300 mg/kg groups,
respectively.; Gastrointestinal: The study text noted that during week 4, the two high-
est dose groups were prepared incorrectly, and for the first three days of that week, the
animals were administered double the target levels. Animals in the 350 mg/kg group,
were instead dosed with 700 mg/kg, and animals in the 700 mg/kg group were dosed
with 1,400 mg/kg. No deaths occurred as a result of the dosing error, but two male mice
had convulsions and labored breathing on the third day of overdosing. Overdosed fe-
males were uncoordinated. These animals were not dosed on the 4th day of the week
to allow them to recover. Dosing resumed on the 5th day. Three males and two females
died during the study due to gavage trauma. The males were from the 175, 350, and 700
mg/kg groups, and the females were from the 175 and 300 mg/kg groups, respectively.;
Thyroid: The study text noted that during week 4, the two highest dose groups were
prepared incorrectly, and for the first three days of that week, the animals were admin-
istered double the target levels. Animals in the 350 mg/kg group, were instead dosed
with 700 mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg.
No deaths occurred as a result of the dosing error, but two male mice had convulsions
and labored breathing on the third day of overdosing. Overdosed females were unco-
ordinated. These animals were not dosed on the 4th day of the week to allow them to
recover. Dosing resumed on the 5th day. Three males and two females died during the
study due to gavage trauma. The males were from the 175, 350, and 700 mg/kg groups,
and the females were from the 175 and 300 mg/kg groups, respectively.
Continued on next page ...
Page 121 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 11 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B„ Dixon, D„ Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15.
Cardiovascular; Endocrine; Gastrointestinal; Lung/Respiratory; Gastrointestinal; Thyroid; Immune/Hematological;
Cardiovascular: Histopathology (heart); heart may have been weighed; Endocrine: Histopathology (adrenal glands); adrenal glands may have been
weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Lung/Respiratory: Histopathology
lung; lungs may have been weighed; Gastrointestinal: Histopathology esophagus and salivary gland; relevant organs may have been weighed; Thyroid:
Histopathology (thyroid); thyroid may have been weighed; Immune/Hematological: Histopathology (spleen, thymus, mesenteric lymph nodes, bone
marrow); organs may have been weighed;
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
Continued metric comment- Immune/Hematological: The study text noted that during
Exposure
week 4, the two highest dose groups were prepared incorrectly, and for the first three
days of that week, the animals were administered double the target levels. Animals in
the 350 mg/kg group, were instead dosed with 700 mg/kg, and animals in the 700 mg/
kg group were dosed with 1,400 mg/kg. No deaths occurred as a result of the dosing
error, but two male mice had convulsions and labored breathing on the third day of
overdosing. Overdosed females were uncoordinated. These animals were not dosed on
the 4th day of the week to allow them to recover. Dosing resumed on the 5th day. Three
males and two females died during the study due to gavage trauma. The males were
from the 175, 350, and 700 mg/kg groups, and the females were from the 175 and 300
mg/kg groups, respectively.
Metric 23:
Data Presentation and Analysis
Low
All Outcomes: Statistical analysis was performed, but the methods used to analyze
initial histopathology data weren't clearly specified, only that the significance level was
set at p < 0.05.
Metric 24:
Reporting of Data
High
All Outcomes: Negative findings for initial histopathology were reported qualitatively in
the text.
Overall Quality Determination
High
Page 122 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 12 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Reproductive/Developmental
Histopathology (epididymis, prostate), sperm morphology and vaginal cytology; reproductive organs may have been weighed
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls High
Positive Controls N/A
Randomized Allocation of Animals Medium
The study included a concurrent negative vehicle (corn oil) control group.
Positive controls are not necessary for this study type.
Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Tox-
icology Program (NTP). The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 123 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 12 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Reproductive/Developmental
Histopathology (epididymis, prostate), sperm morphology and vaginal cytology; reproductive organs may have been weighed
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13:
Test Animal Characteristics
Medium
The study used male and female F344/N rats. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Metric 14:
Adequacy and Consistency of Animal
Medium
Animal husbandry (caging, food and water access, temperature, humidity, and light
Husbandry Conditions
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that stat humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was appropriate. It is unclear whether the deviations in animal
husbandry conditions had an impact on the study results.
Metric 15:
Number of Animals per Group
Medium
The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Medium
The methods did not indicate whether any reproductive organ weights were mea-
sured; only that organs (unspecified) were weighed. At necropsy, relevant tissues were
histopathologically examined. The study referenced Dunnick et al. 1984 for methods
on sperm morphology and vaginal cytology (reviewed for this evaluation). It is not clear
whether sperm assessments were conducted on animals that died prior to the end of the
study. Overall, the methods were sensitive for the outcomes of interest.
Metric 17:
Consistency of Outcome Assessment
High
There is no indication that there were inconsistencies in the outcome assessment across
groups. Histopathology was performed at the end of the study.
Metric 18:
Sampling Adequacy
Medium
The methods did not specify whether sperm morphology and vaginal cytology analysis
were conducted in all groups. Except for brain tissues, histopathology was conducted in
controls and animals from the 175 and 350 mg/kg-day groups.
Metric 19:
Blinding of Assessors
N/A
Blinding is not necessary for initial histopathology.
Metric 20:
Negative Control Response
Medium
The biological responses of negative controls were not explicitly reported. Negative
findings were qualitatively reported in the text.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
Medium
Some information to determine confounding (initial body weights) was not provided.
The study did not measure food or water intake, but this was not a dietary or drink-
ing water study, and these endpoints are not required for this study type according to
NTP.The study text mentioned technical difficulties that prevented accurate analysis of
sperm morphology in rats. No further details were provided.
Continued on next page ...
Page 124 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 12 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Reproductive/Developmental
Histopathology (epididymis, prostate), sperm morphology and vaginal cytology; reproductive organs may have been weighed
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg-day group, were instead dosed with
350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with 700 mg/kg-
day. As a result, 2 females in each group died, and others showed excessive signs of
acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The overdose
caused no deaths in males, and they showed no signs of toxicity. The surviving animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed on
the 5th day. In addition to these deaths, three animals died due to gavage error including
1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/kg-day.
Metric 23:
Data Presentation and Analysis
Low
Statistical analysis was performed, but the methods used to analyze initial histopathol-
ogy data weren't clearly specified, only that the significance level was set at p < 0.05.
Metric 24:
Reporting of Data
Low
Negative findings for initial histopathology were reported qualitatively in the text.
Sperm data were not generated due to technical difficulties. Vaginal cytology was pur-
portedly conducted, but these data were not reported.
Overall Quality Determination
Medium
Page 125 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 13 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Reproductive/Developmental
Histopathology (epididymis, prostate), sperm morphology and vaginal cytology; reproductive organs may have been weighed
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls High
Positive Controls N/A
Randomized Allocation of Animals Medium
The study included a concurrent negative vehicle (corn oil) control group.
Positive controls are not necessary for this study type.
Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Tox-
icology Program (NTP). The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 126 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 13 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Reproductive/Developmental
Histopathology (epididymis, prostate), sperm morphology and vaginal cytology; reproductive organs may have been weighed
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13:
Test Animal Characteristics
Medium
The study used male and female B6C3F1 mice. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Metric 14:
Adequacy and Consistency of Animal
Medium
Animal husbandry (caging, food and water access, temperature, humidity, and light
Husbandry Conditions
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that state humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was reported. NTP guidelines specify that male mice should
always be housed individually. It is unclear whether the deviations in animal husbandry
conditions had an impact on the study results.
Metric 15:
Number of Animals per Group
Medium
The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Medium
The methods did not indicate whether any reproductive organ weights were mea-
sured; only that organs (unspecified) were weighed. At necropsy, relevant tissues were
histopathologically examined. The study referenced Dunnick et al. 1984 for methods
on sperm morphology and vaginal cytology (reviewed for this evaluation). It is not clear
whether sperm assessments were conducted on animals that died prior to the end of the
study. Overall, the methods were sensitive for the outcomes of interest.
Metric 17:
Consistency of Outcome Assessment
High
There is no indication that there were inconsistencies in the outcome assessment across
groups. Histopathology was performed at the end of the study.
Metric 18:
Sampling Adequacy
Medium
Sperm morphology was determined in all male mice surviving to terminal sacrifice. The
methods did not specify whether vaginal cytology analysis was conducted in all groups.
Histopathology was conducted in control animals and animals from the high-dose group.
Metric 19:
Blinding of Assessors
N/A
Blinding is not necessary for initial histopathology.
Metric 20:
Negative Control Response
Medium
The biological responses of negative controls were not explicitly reported. Negative
findings were qualitatively reported in the text.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
Medium
Some information to determine confounding (initial body weights) was not provided.
The study did not measure food or water intake, but this was not a dietary or drink-
ing water study, and these endpoints are not required for this study type according to
NTP.The study text mentioned technical difficulties that prevented accurate analysis of
sperm morphology in rats. No further details were provided.
Continued on next page ...
Page 127 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 13 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Reproductive/Developmental
Histopathology (epididymis, prostate), sperm morphology and vaginal cytology; reproductive organs may have been weighed
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared in-
Exposure
correctly, and for the first three days of that week, the animals were administered double
the target levels. Animals in the 350 mg/kg group, were instead dosed with 700 mg/kg,
and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths occurred
as a result of the dosing error, but two male mice had convulsions and labored breathing
on the third day of overdosing. Overdosed females were uncoordinated. These animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed on
the 5th day. Three males and two females died during the study due to gavage trauma.
The males were from the 175, 350, and 700 mg/kg groups, and the females were from
the 175 and 300 mg/kg groups, respectively.
Metric 23:
Data Presentation and Analysis
Low
Statistical analysis was performed, but the methods used to analyze initial histopathol-
ogy data weren't clearly specified, only that the significance level was set at p < 0.05.
Metric 24:
Reporting of Data
Medium
Negative findings for initial histopathology were reported qualitatively in the text.
Sperm counts were significantly decreased at the high dose. Vaginal cytology was pur-
portedly conducted, but these data were not reported.
Overall Quality Determination
Medium
Page 128 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 14 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Clinical observations
Unspecified clinical observations
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls High
Positive Controls N/A
Randomized Allocation of Animals Medium
The study included a concurrent negative vehicle (corn oil) control group.
Positive controls are not necessary for this study type.
Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Tox-
icology Program (NTP). The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 129 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 14 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Clinical observations
Unspecified clinical observations
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female B6C3F1 mice. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Medium Animal husbandry (caging, food and water access, temperature, humidity, and light
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that state humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was reported. NTP guidelines specify that male mice should
always be housed individually. It is unclear whether the deviations in animal husbandry
conditions had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Medium Animals were subjected to clinical examinations weekly in accordance with NTP guide-
lines. No methodological details were provided. The guideline also specifies that ex-
panded clinical observations should be done by a pathologist at a minimum at least once
every other week. It is unclear if this was done.
High Based on the information provided, all animals were observed daily. Additional outcome
assessment methods (e.g., the time of observations (time of day)) were not provided,
but based on the available information, there is no indication that there were differences
across groups (except for those associated with the overdose).
Medium All animals were observed for clinical signs, but because negative findings were qualita-
tively reported, the sample size cannot be verified.
Medium Blinding was not reported and clinical signs can be somewhat subjective in nature; how-
ever, lack of blinding is not expected to have a significant impact on results because no
clinical signs of toxicity were observed.
Medium The appropriateness of the negative control response cannot be definitively determined
because incidence data were not reported. The text mentioned some clinical signs in
treated animals but did not explicitly report that there were no clinical signs in controls.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium Some information to determine confounding (initial body weights) was not provided.
and Procedures The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
Continued on next page ...
Page 130 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 14 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Clinical observations
Unspecified clinical observations
Chronic (>91 days) 16 weeks - Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 350 mg/kg group, were instead dosed with 700
mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths
occurred as a result of the dosing error, but two male mice had convulsions and labored
breathing on the third day of overdosing. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 300 mg/kg groups,
respectively.
Metric 23:
Data Presentation and Analysis
N/A
The only observed clinical signs were those unrelated to exposure. Statistical analysis
was not necessary for clearly negative findings across groups.
Metric 24:
Reporting of Data
Medium
Clinical signs related to the overdose were noted in two males and all females. No clini-
cal signs unrelated to the overdose were described.
Overall Quality Determination
Medium
Page 131 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 15 of 15
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Clinical observations
Unspecified clinical observations
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was clearly identified as tris(2-chloroethyl)phosphate.
High The test substance was purchased from Stauffer Chemical Company. The lot and batch
number were provided.
Low The purity was not reported and could not be determined on the manufacturer's website.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls High
Positive Controls N/A
Randomized Allocation of Animals Medium
The study included a concurrent negative vehicle (corn oil) control group.
Positive controls are not necessary for this study type.
Animals were assigned to dose groups and to cages using a random number table. It was
not specified whether animals were also normalized to starting body weights.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Fresh solutions were made every two weeks by dissolving the test material in 100%
pure corn oil. Test solutions were stored at 5 degrees C until use. Details of mixing for
homogeneity weren't provided. Testing for stability was not discussed.
High Sufficient exposure administration details were reported. A consistent gavage volume of
5 mL/kg was used. The time of day of dosing was not specified.
Medium Doses were clearly reported. Dosing solutions were analyzed (method and frequency not
specified), and the text indicated that the actual concentrations administered remained
within 10% of the target. Analytical values were not provided.
Medium The study did not mention adherence to a specific guideline, but the text indicated this
was an NTP study. Animals were dosed 5 days per week, consistent with the "Specifi-
cations for the Conduct of Studies to Evaluate the Toxic and Carcinogenic Potential of
Chemical, Biological and Physical Agents in Laboratory Animals for the National Tox-
icology Program (NTP). The study duration was 16 weeks. The authors did not provide
justification for this duration. This is longer than a typical 90-day subchronic study, and
shorter than an NTP chronic/carcinogenicity study.
High The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Continued on next page .
Page 132 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 15 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Clinical observations
Unspecified clinical observations
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female F344/N rats. The test animal source (Charles River
Breeding Laboratories), and age purchase (5 weeks old), were reported. Initial body
weights were not specified. A quarantine period was mentioned, but the duration was
not reported.
Medium Animal husbandry (caging, food and water access, temperature, humidity, and light
cycle) were reported. The relative humidity varied from 10% to 78% . This deviates
from NTP guidelines that stat humidity should not be below 35% or above 65% . The
temperature range in the study was 70 to 81 degrees. NTP indicates temperature should
not be above 75 degrees, and that there should be minimal fluctuations. The number of
animals per cage (n =5) was appropriate. It is unclear whether the deviations in animal
husbandry conditions had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Medium Animals were subjected to clinical examinations weekly in accordance with NTP guide-
lines. No methodological details were provided. The guideline also specifies that ex-
panded clinical observations should be done by a pathologist at a minimum at least once
every other week. It is unclear if this was done.
High Based on the information provided, all animals were observed daily. Additional outcome
assessment methods (e.g., the time of observations (time of day)) were not provided,
but based on the available information, there is no indication that there were differences
across groups (except for those associated with the overdose).
Medium All animals were observed for clinical signs, but since negative findings were qualita-
tively reported, the sample size cannot be verified.
Medium Blinding was not reported and clinical signs can be somewhat subjective in nature; how-
ever, lack of blinding is not expected to have a significant impact on results because no
clinical signs of toxicity were observed.
Medium The appropriateness of the negative control response cannot be definitively determined
because incidence data were not reported, the text mentioned some clinical signs in
treated animals but did not explicitly report that there were no clinical signs in controls.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium Some information to determine confounding (initial body weights) was not provided.
and Procedures The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
Continued on next page ...
Page 133 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469641 Table: 15 of 15
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Matthews, H. B., Dixon, D., Herr, D, W„ Tilson, H, (1990), Subchronic toxicity studies indicate that tris(2-chloroethyl)phosphate administration results in
lesions in the rat hippocampus. Toxicology and Industrial Health 6( 1): 1-15,
Clinical observations
Unspecified clinical observations
Chronic (>91 days) 16 weeks - Rats and Mice
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469641
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg-day group, were instead dosed with
350 mg/kg-day, and animals in the 350 mg/kg-day group were dosed with 700 mg/kg-
day. As a result, 2 females in each group died, and others showed excessive signs of
acute toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The overdose
caused no deaths in males, and they showed no signs of toxicity. The surviving animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed on
the 5th day. In addition to these deaths, three animals died due to gavage error including
1 male and 1 female at 22 mg/kg-day and 1 female at 175 mg/kg-day.
Metric 23:
Data Presentation and Analysis
Low
Some data were clearly statistically analyzed, but the statistical methods used were not
reported; the study text only specifies that the "Significance level was set at p < 0.05)."
It is unclear whether clinical observations were statistically analyzed, and incidence data
were not provided for an independent review.
Metric 24:
Reporting of Data
Medium
Clinical signs related to the overdose were noted and a qualitative statement indicated
seizures were observed in high-dose female rats during week 12. Incidence and signifi-
cance were not specified.
Overall Quality Determination
Medium
Page 134 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 1 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cancer/Carcinogenesis
Tumor incidence
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
High Animals were dosed with 0, 44, or 88 mg/kg/day, 5 days per week. Doses were selected
based on a subchronic study. Dose formulations were analyzed at approximately 8-week
intervals by gas chromatography, and remained within 10% of the target concentrations
throughout the course of the study. The target and measured concentrations in the solu-
tions (mg/mL) were reported.
High Animals were dosed 5 days per week for two years. The exposure frequency and dura-
tion are consistent with NTP guidelines.
Continued on next page ...
Page 135 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 1 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cancer/Carcinogenesis
Tumor incidence
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Low This 2-year study only included two treatment groups and a control. Although the au-
thors justified the doses used, NTP guidelines specify using 3 treatment groups plus a
control. Effects were observed at both doses and a NOAEL could not be determined.
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Metric 14:
Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Low The study used male and female F344/N rats. The test animal source (Harlan industries)
and age at the start of the study (8-10 weeks old) were reported. Although initial ani-
mal body weights for the 16-day and 16-week studies were reported, the initial body
weights for the 2-year study are not reported. Body weight data begin after 1 week of
dosing.NTP no longer uses F344/N rats for chronic/carcinogenicity studies. It was de-
termined that these rats have a high background in some tumors including testicular
interstitial cell tumors and mononuclear cell leukemia. The high backgrounds could
decrease the ability to detect exposure-related effects in these organs/systems.
Low The number of animals per cage (5/cage) was reported. According to NTP guidelines for
chronic/carcinogenicity studies, male rats should only be housed up to 3 per cage. Food
and water were provided ad libiutm. Animal room environments (temperature, humidity,
lighting were reported. The humidity ranged considerably from 15% to 84% . This
deviates from NTP guidelines which state humidity should not be below 35% or above
65% . Similarly, the temperature range was reported to be between 60 and 86 degrees F.
NTP guidelines state that the temperatures shall not be below 69 or above 75 degrees F,
with minimal fluctuations. It is unclear whether these deviations had a significant impact
on the study results.
Medium The study methods specify 50/sex/group which is consistent with NTP guidelines for a
chronic/carcinogenicity study. An extra 10/sex/group were added for an interim sacrifice
at 66 weeks.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology High A detailed description of histopathology and tumor assessment methods at terminal
sacrifice was provided. The methods were sensitive to the outcomes of interest and
adhered to NTP guidelines.
Metric 17: Consistency of Outcome Assessment High The same protocol was applied to animals from all groups, and animals were consis-
tently assessed for the outcomes of interest.
Metric 18: Sampling Adequacy Low The sampling was adequate. All animals from all groups were assessed for carcino-
genicity.
Continued on next page ...
Page 136 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 1 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cancer/Carcinogenesis
Tumor incidence
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Metric 19: Blinding of Assessors High The study indicated that all histopathology data were sent to an independent quality
assessment laboratory and slides, tissue counts, and histo-technique were evaluated.
Additionally, all tumor diagnoses, all tissue sections of the brain, kidney, liver, spleen,
and thyroid, and tissues randomly selected from 10% of the animals were re-examined
by a pathologist. It was not specified whether these examinations were done blinded;
however, in any instances where there was a disagreement in diagnosis, a Pathology
Working Group chairperson, reviewed the slides blinded without prior knowledge of the
dose group, or the previous diagnoses.
Metric 20: Negative Control Response Medium Incidences in control animals were generally low, but there were a few exceptions.
There was a high incidence of testes adenomas in the controls (38/50 overall, and 33/
36 at terminal sacrifice). The incidences of pituitary gland adenomas (39% ) and ade-
nomas or carcinomas (43% ) were higher in control rats than in treated rats (29% in
the high-dose group), and the incidence of thyroid gland adenomas or adenomas and
carcinomas in control rats was higher than in the treated rats (28% overall, and 33%
of controls at terminal sacrifice had tumors). Based on NTP historical control data for
rats of this strain, these percentages fall within historical ranges, and therefore are not
unexpected.Citation: Haseman JK, Hailey JR, Morris RW. Spontaneous Neoplasm In-
cidences in Fischer 344 Rats and B6C3F1 Mice in Two-Year Carcinogenicity Studies:
A National Toxicology Program Update. Toxicologic Pathology. 1998;26(3):428-441.
doi: 10.1177/019262339802600318
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
High No confounding variables in the test design and procedures were identified. The study
did not measure food or water intake, but this was not a dietary or drinking water study,
and these endpoints are not required for this study type according to NTP. There were no
significant body weight changes that were suggestive of palatability issues.
Medium Gavage-related deaths were noted in 4 controls (all males), 4 animals at 44 mg/kg-day
(1 male, 3 females), and 4 at 88 mg/kg-day (all females). There were also 3 accidental
deaths; details were only provided for one high-dose male that was inadvertently killed
at the 66-week interim sacrifice. The small number of deaths not related to exposure is
not expected to have a significant impact on the study results.
High A detailed description of statistical methods used to analyze tumor data was provided
and was appropriate.
High Tumor data were reported in detail and included summary tables with statistical results,
and tables showing individual animal tumor pathology.
Overall Quality Determination
High
Page 137 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 2 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality (Clinical signs)
Survival
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
High Animals were dosed with 0, 44, or 88 mg/kg/day, 5 days per week. Doses were selected
based on a subchronic study. Dose formulations were analyzed at approximately 8-week
intervals by gas chromatography, and remained within 10% of the target concentrations
throughout the course of the study. The target and measured concentrations in the solu-
tions (mg/mL) were reported.
High Animals were dosed 5 days per week for two years. The exposure frequency and dura-
tion are consistent with NTP guidelines.
Low This 2-year study only included two treatment groups and a control. Although the au-
thors justified the doses used, NTP guidelines specify using 3 treatment groups plus a
control. Effects were observed at both doses and a NOAEL could not be determined.
Continued on next page ...
Page 138 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 2 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality (Clinical signs)
Survival
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 12:
Exposure Route and Method
High
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Medium
The study used male and female F344/N rats. The test animal source (Harlan industries)
and age at the start of the study (8-10 weeks old) were reported. Although initial animal
body weights for the 16-day and 16-week studies were reported, the initial body weights
for the 2-year study are not reported. Body weight data begin after 1 week of dosing.
Metric 14:
Adequacy and Consistency of Animal
Low
The number of animals per cage (5/cage) was reported. According to NTP guidelines for
Husbandry Conditions
chronic/carcinogenicity studies, male rats should only be housed up to 3 per cage. Food
and water were provided ad libiutm. Animal room environments (temperature, humidity,
lighting were reported. The humidity ranged considerably from 15% to 84% . This
deviates from NTP guidelines which state humidity should not be below 35% or above
65% . Similarly, the temperature range was reported to be between 60 and 86 degrees F.
NTP guidelines state that the temperatures shall not be below 69 or above 75 degrees F,
with minimal fluctuations. It is unclear whether these deviations had a significant impact
on the study results.
Metric 15:
Number of Animals per Group
Medium
The study methods specify 50/sex/group which is consistent with NTP guidelines for a
chronic/carcinogenicity study, plus an extra 10/sex/group for an interim sacrifice.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
Animals were observed twice daily for morbidity and mortality. The outcome assess-
ment was sensitive and appropriate for the outcome of interest.
Metric 17:
Consistency of Outcome Assessment
High
The same protocol was applied to animals from all groups, and animals were consis-
tently assessed for the outcomes of interest.
Metric 18:
Sampling Adequacy
High
All animals were assessed for mortality.
Metric 19:
Blinding of Assessors
N/A
Blinding is not necessary because this outcome of interest is either not subjective in
nature, or blinding is not required (e.g., initial histopathology).
Metric 20:
Negative Control Response
High
The negative control responses were reported and were adequate.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
High
No confounding variables in the test design and procedures were identified. The study
did not measure food or water intake, but this was not a dietary or drinking water study,
and these endpoints are not required for this study type according to NTP. There were no
significant body weight changes that were suggestive of palatability issues.
Continued on next page ...
Page 139 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 2 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality (Clinical signs)
Survival
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Medium
Gavage-related deaths were noted in 4 controls (all males), 4 animals at 44 mg/kg-day
Exposure
(1 male, 3 females), and 4 at 88 mg/kg-day (all females). There were also 3 accidental
deaths; details were only provided for one high-dose male that was inadvertently killed
at the 66-week interim sacrifice. The small number of deaths not related to exposure is
not expected to have a significant impact on the study results.
Metric 23:
Data Presentation and Analysis
High
Survival data were statistically analyzed and the methods were reported and appropriate
for the data set.
Metric 24:
Reporting of Data
High
Survival curves were provided. A table also reports the total number of natural deaths,
moribund kills, gavage deaths, accidental deaths, animals at interim sacrifices, and the
number surviving to study termination. Survival data were statistically analyzed.
Overall Quality Determination
High
Page 140 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 3 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations (Clinical signs)
Clinical signs (clinical observations)
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
Metric 2: Test Substance Source High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
Metric 3: Test Substance Purity High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
N/A Positive controls are not required for this study type.
Medium Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Metric 10:
Metric 11:
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations High
Exposure Frequency and Duration High
Number of Exposure Groups and Low
Dose/Concentration Spacing
Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
The doses were clearly reported. Animals were exposed to 0, 175, or 350 mg/kg, 5 days
per week. Adjusted or time-weighted average doses in mg/kg-day were not provided,
but can be determined using the data provided. Dose formulations were analyzed at
approximately 8-week intervals by gas chromatography, and remained within 10% of
the target concentrations throughout the course of the study. The target and measured
concentrations in the solutions (mg/mL) were reported.
Animals were dosed 5 days per week for two years. The exposure frequency and dura-
tion are consistent with NTP guidelines.
This 2-year study only included two treatment groups and a control. Although the au-
thors justified the doses used, NTP guidelines specify using 3 treatment groups plus a
control. Effects were observed at both doses and a NOAEL could not be determined.
Continued on next page ...
Page 141 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 3 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations (Clinical signs)
Clinical signs (clinical observations)
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 12: Exposure Route and Method
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13:
Metric 14:
Test Animal Characteristics
Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (8-9 weeks old) were reported. Although initial an-
imal body weights for the 16-day and 16-week studies were reported, the initial body
weights for the 2-year study are not reported. Body weight data begin after 1 week of
dosing.This strain of mouse is known to have a high background incidence of hepatocel-
lular adenomas in males. This strain may not be appropriate for identifying treatment-
induced tumors of this type.
Low The number of animals per cage (5/cage) was reported. According to NTP guidelines
for chronic/carcinogenicity studies, male mice should be housed individually. Food and
water were provided ad libiutm. Animal room environments (temperature, humidity,
lighting were reported. The humidity ranged considerably from 15% to 84% . This
deviates from NTP guidelines which state humidity should not be below 35% or above
65% .Similarly, the temperature range was reported to be between 60 and 86 degrees F.
NTP guidelines state that the temperatures shall not be below 69 or above 75 degrees F,
with minimal fluctuations. It is unclear whether these deviations had an impact on the
study results.
Medium The study methods specify 50/sex/group which is consistent with NTP guidelines for a
chronic/carcinogenicity study. An extra 10/sex/group were added for an interim sacrifice
at 66 weeks.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Outcome Assessment Methodology High
Consistency of Outcome Assessment High
Sampling Adequacy High
A detailed description of histopathology and tumor assessment methods at terminal
sacrifice was provided. The methods were sensitive to the outcomes of interest and
adhered to NTP guidelines.
The same protocol was applied to animals from all groups, and animals were consis-
tently assessed for the outcomes of interest.
A sufficient number of animals were sampled to assess carcinogenicity.
Continued on next page ...
Page 142 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 3 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations (Clinical signs)
Clinical signs (clinical observations)
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High The study indicated that all histopathology data were sent to an independent quality
assessment laboratory and slides, tissue counts, and histotechnique were evaluated.
Additionally, all tumor diagnoses, all tissue sections of the brain, kidney, liver, spleen,
and thyroid, and tissues randomly selected from 10% of the animals were re-examined
by a pathologist. It was not specified whether these examinations were done blinded;
however, in any instances where there was a disagreement in diagnosis, a Pathology
Working Group chairperson, reviewed the slides without prior knowledge of the dose
group, or the previous diagnoses.
Medium 52% of control male mice overall had hepatocellular adenomas or carcinomas. Due to
the high background, the increased incidences in the treatment groups were not statisti-
cally significant. However, based on NTP historical control data for this strain (available
on the NTP website), the background level is expected for this strain of mouse. Neoplas-
tic incidences of control mice in other tissues were appropriate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
High No confounding variables in the test design and procedures were identified. The study
did not measure food or water intake, but this was not a dietary or drinking water study,
and these endpoints are not required for this study type according to NTP. There were no
significant body weight changes that were suggestive of palatability issues.
Medium Two control and two high-dose male mice, and one control female mouse, all predes-
ignated for the interim sacrifice died before week 66. The causes of death were not
specified. Overall, several gavage deaths of both sexes were also noted across groups.
These deaths are not expected to have a significant impact on the study results.
High Statistical methods for analyzing tumor data were described in detail and were appropri-
ate. Statistical significance was shown where appropriate.
High Cancer data were adequately reported including summary tables, and individual animal
data.
Overall Quality Determination
High
Page 143 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 4 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
N/A Positive controls are not required for this study type.
Medium Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
High The doses were clearly reported. Animals were exposed to 0, 175, or 350 mg/kg, 5 days
per week. Adjusted or time-weighted average doses in mg/kg-day were not provided,
but can be determined using the data provided. Dose formulations were analyzed at
approximately 8-week intervals by gas chromatography, and remained within 10% of
the target concentrations throughout the course of the study. The target and measured
concentrations in the solutions (mg/mL) were reported.
High Animals were dosed 5 days per week for two years. The exposure frequency and dura-
tion are consistent with NTP guidelines.
Low This 2-year study only included two treatment groups and a control. Although the au-
thors justified the doses used, NTP guidelines specify using 3 treatment groups plus a
control. Effects were observed at both doses and a NOAEL could not be determined.
Continued on next page ...
Page 144 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 4 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 12: Exposure Route and Method
High Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Medium
Low
Metric 15: Number of Animals per Group
Medium
The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (8-9 weeks old) were reported. Although initial animal
body weights for the 16-day and 16-week studies were reported, the initial body weights
for the 2-year study are not reported. Body weight data begin after 1 week of dosing.
The number of animals per cage (5/cage) was reported. According to NTP guidelines
for chronic/carcinogenicity studies, male mice should be housed individually. Food and
water were provided ad libitum. Animal room environments (temperature, humidity,
lighting) were reported. The humidity ranged considerably from 15% to 84% . This
deviates from NTP guidelines which state humidity should not be below 35% or above
65% .Similarly, the temperature range was reported to be between 60 and 86 degrees F.
NTP guidelines state that the temperatures shall not be below 69 or above 75 degrees F,
with minimal fluctuations. It is unclear whether these deviations had an impact on the
study results.
The study methods specify 50/sex/group which is consistent with NTP guidelines for a
chronic/carcinogenicity study. An extra 10/sex/group were added for an interim sacrifice
at 66 weeks.
Domain 5: Outcome Assessment
Metric
16:
Outcome Assessment Methodology
High
Animals were observed twice daily for morbidity and mortality. The outcome assess-
ment was sensitive and appropriate for the outcome of interest.
Metric
17:
Consistency of Outcome Assessment
High
The same protocol was applied to animals from all groups, and animals were consis-
tently assessed for the outcomes of interest.
Metric
18:
Sampling Adequacy
High
All animals were assessed for mortality.
Metric
19:
Blinding of Assessors
Medium
Blinding was not reported, but blinding is not necessary because this outcome of interest
is either not subjective in nature, or blinding is not required for this endpoint (e.g., initial
histopathology).
Metric
20:
Negative Control Response
High
The survival of control animals was appropriate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design High No confounding variables in the test design and procedures were identified. The study
and Procedures did not measure food or water intake, but this was not a dietary or drinking water study,
and these endpoints are not required for this study type according to NTP. There were no
significant body weight changes that were suggestive of palatability issues.
Continued on next page ...
Page 145 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 4 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 22:
Metric 23:
Metric 24:
Health Outcomes Unrelated to
Exposure
Data Presentation and Analysis
Reporting of Data
Medium
High
High
Two control and two high-dose male mice, and one control female mouse, all predes-
ignated for the interim sacrifice died before week 66. The causes of death were not
specified. Overall, several gavage deaths of both sexes were also noted across groups.
These deaths are not expected to have a significant impact on the study results.
Survival data were statistically analyzed and the methods were reported and appropriate
for the data set.
Survival curves were provided. A table also reports the total number of natural deaths,
moribund kills, gavage deaths, accidental deaths, animals at interim sacrifices, and the
number surviving to study termination. Survival data were statistically analyzed.
Overall Quality Determination
High
Page 146 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 5 of 28
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Gastrointestinal; Ocular/Sensory; Lung/Respiratory;
Outcome(s):
Reported Health Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
Effect(s): intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory:
Gross necropsy, histopathology (lung, nose, trachea);
Duration: Chronic (>91 days) 2-yrs (104 weeks- mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1; Test Substance Identity
Metric 2; Test Substance Source
Metric 3; Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2; Test Design
Metric 4; Negative and Vehicle Controls High
Metric 5; Positive Controls N/A
Metric 6; Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3; Exposure Characterization
Metric 7; Preparation and Storage of Test
Substance
Metric 8; Consistency of Exposure
Administration
Metric 9; Reporting of Doses/Concentrations
Metric 10; Exposure Frequency and Duration
High All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
High All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
High All Outcomes: The doses were clearly reported. Animals were exposed to 0, 175, or
350 mg/kg, 5 days per week. Adjusted or time-weighted average doses in mg/kg-day
were not provided, but can be determined using the data provided. Dose formulations
were analyzed at approximately 8-week intervals by gas chromatography, and remained
within 10% of the target concentrations throughout the course of the study. The target
and measured concentrations in the solutions (mg/mL) were reported.
High All Outcomes: Animals were dosed 5 days per week for two years. The exposure fre-
quency and duration are consistent with NTP guidelines.
Continued on next page ...
Page 147 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 5 of 28
Domain
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Gastrointestinal; Ocular/Sensory; Lung/Respiratory;
Outcome(s):
Reported Health Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
Effect(s): intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory:
Gross necropsy, histopathology (lung, nose, trachea);
Duration: Chronic (>91 days) 2-yrs (104 weeks- mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Metric
Rating
Comments
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12; Exposure Route and Method
Low All Outcomes: This 2-year study only included two treatment groups and a control.
Although the authors justified the doses used, NTP guidelines specify using 3 treatment
groups plus a control. Effects were observed at both doses and a NOAEL could not be
determined.
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4; Test Animals
Metric 13; Test Animal Characteristics Medium All Outcomes: The study used male and female B6C3F1 mice. The test animal source
(Harlan industries), age at the start of the study (8-9 weeks old) were reported. Although
initial animal body weights for the 16-day and 16-week studies were reported, the initial
body weights for the 2-year study are not reported. Body weight data begin after 1 week
of dosing.
Continued on next page ...
Page 148 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 5 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Gastrointestinal; Ocular/Sensory; Lung/Respiratory;
Outcome(s):
Reported Health Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
Effect(s): intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory:
Gross necropsy, histopathology (lung, nose, trachea);
Duration: Chronic (>91 days) 2-yrs (104 weeks- mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 14; Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15; Number of Animals per Group
Low Gastrointestinal: The number of animals per cage (5/cage) was reported. According
to NTP guidelines for chronic/carcinogenicity studies, male mice should be housed
individually. Food and water were provided ad libiutm. Animal room environments
(temperature, humidity, lighting were reported. The humidity ranged considerably from
15% to 84% . This deviates from NTP guidelines which state humidity should not be
below 35% or above 65% .Similarly, the temperature range was reported to be between
60 and 86 degrees F. NTP guidelines state that the temperatures shall not be below 69
or above 75 degrees F, with minimal fluctuations. It is unclear whether these deviations
had an impact on the study results.; Ocular/Sensory: The number of animals per cage
(5/cage) was reported. According to NTP guidelines for chronic/carcinogenicity studies,
male mice should be housed individually. Food and water were provided ad libitum. An-
imal room environments (temperature, humidity, lighting) were reported. The humidity
ranged considerably from 15% to 84% . This deviates from NTP guidelines which state
humidity should not be below 35% or above 65% .Similarly, the temperature range was
reported to be between 60 and 86 degrees F. NTP guidelines state that the temperatures
shall not be below 69 or above 75 degrees F, with minimal fluctuations. It is unclear
whether these deviations had an impact on the study results.; Lung/Respiratory: The
number of animals per cage (5/cage) was reported. According to NTP guidelines for
chronic/carcinogenicity studies, male mice should be housed individually. Food and
water were provided ad libiutm. Animal room environments (temperature, humidity,
lighting were reported. The humidity ranged considerably from 15% to 84% . This devi-
ates from NTP guidelines which state humidity should not be below 35% or above 65%
.Similarly, the temperature range was reported to be between 60 and 86 degrees F. NTP
guidelines state that the temperatures shall not be below 69 or above 75 degrees F, with
minimal fluctuations. It is unclear whether these deviations had an impact on the study
results.
Medium All Outcomes: The study methods specify 50/sex/group which is consistent with NTP
guidelines for a chronic/carcinogenicity study. An extra 10/sex/group were added for an
interim sacrifice at 66 weeks.
Domain 5; Outcome Assessment
Metric 16; Outcome Assessment Methodology High All Outcomes: The study included interim sacrifices (10/sex/group) at 66-weeks. These
animals were subjected to gross necropsy and histopathology. Histopathological exami-
nation of non-neoplastic lesions was also conducted in the main group of animals at the
terminal sacrifice. A detailed description of histopathological procedures was provided
and the methods were sensitive to the outcomes of interest.
Metric 17; Consistency of Outcome Assessment High All Outcomes: Details of the outcome assessment protocol were reported and the out-
comes were consistently assessed for the groups that were examined.
Continued on next page ...
Page 149 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 5 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Gastrointestinal; Ocular/Sensory; Lung/Respiratory;
Outcome(s):
Reported Health Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
Effect(s): intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory:
Gross necropsy, histopathology (lung, nose, trachea);
Duration: Chronic (>91 days) 2-yrs (104 weeks- mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 18;
Sampling Adequacy
High
Gastrointestinal: At both the 66-week and 104-week terminal sacrifices, histopathologi-
cal analysis was conducted on tissues from the control and high-dose animals, except for
tissues from the harderian gland, kidney, liver, lung, and stomach (this outcome), which
were also examined from low-dose animals.; Ocular/Sensory: At both the 66-week
and 104-week terminal sacrifices, histopathological analysis was conducted on tissues
from the control and high-dose animals, except for tissues from the harderian gland,
kidney, liver, lung, and stomach, which were also examined from low-dose animals.;
Lung/Respiratory: At both the 66-week and 104-week terminal sacrifices, histopatholog-
ical analysis was conducted on tissues from the control and high-dose animals, except
for tissues from the harderian gland, kidney, liver, lung, and stomach, which were also
examined from low-dose animals.
Metric 19;
Blinding of Assessors
Medium
All Outcomes: The study indicated that all histopathology data were sent to an indepen-
dent quality assessment laboratory and slides, tissue counts, and histotechnique were
evaluated. Blinding was not reported but is not required for initial histopathology.
Metric 20;
Negative Control Response
Medium
All Outcomes: Non-neoplastic control data from the main group animals were reported
and the incidences were appropriate. Histopathology results from the 66-interim sacri-
fice were not reported. Gross pathological control responses were not reported.
Domain 6; Confounding / Variable Control
Metric 21; Confounding Variables in Test Design
and Procedures
Metric 22; Health Outcomes Unrelated to
Exposure
Metric 23; Data Presentation and Analysis
Metric 24; Reporting of Data
High All Outcomes: No confounding variables in the test design and procedures were identi-
fied. The study did not measure food or water intake, but this was not a dietary or drink-
ing water study, and these endpoints are not required for this study type according to
NTP. There were no significant body weight changes that were suggestive of palatability
issues.
Medium All Outcomes: Two control and two high-dose male mice, and one control female
mouse, all predesignated for the interim sacrifice died before week 66. The causes of
death were not specified. Overall, several gavage deaths of both sexes were also noted
across groups. These deaths are not expected to have a significant impact on the study
results.
High All Outcomes: Statistical methods were adequately described and were appropriate for
the datasets. Statistical significance was shown where appropriate.
Low All Outcomes: Incidence data of non-neoplastic lesions from the main group animals
were adequately reported, although measures of severity were not included. Histopathol-
ogy results from the 66-week interim sacrifice were not reported, and no results for
gross examinations were reported.
Continued on next page ...
Page 150 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 5 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Gastrointestinal; Ocular/Sensory; Lung/Respiratory;
Outcome(s):
Reported Health Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
Effect(s): intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory:
Gross necropsy, histopathology (lung, nose, trachea);
Duration: Chronic (>91 days) 2-yrs (104 weeks- mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain Metric
Rating
Comments
Overall Quality Determination
High
Page 151 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 6 of 28
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Nutritional/Metabolic (Clinical signs); Neurological/Behavioral (Clinical signs);
Outcome(s):
Reported Health Nutritional/Metabolic (Clinical signs): Body weights; Neurological/Behavioral (Clinical signs): Serum cholinesterase activity (special study 16-day and
Effect(s): 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy, histopathology (brain);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
High All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
High All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
High All Outcomes: Animals were dosed with 0, 44, or 88 mg/kg/day, 5 days per week.
Doses were selected based on a subchronic study. Dose formulations were analyzed
at approximately 8-week intervals by gas chromatography, and remained within 10% of
the target concentrations throughout the course of the study. The target and measured
concentrations in the solutions (mg/mL) were reported.
High All Outcomes: Animals were dosed 5 days per week for two years. The exposure fre-
quency and duration are consistent with NTP guidelines.
Low All Outcomes: This 2-year study only included two treatment groups and a control.
Although the authors justified the doses used, NTP guidelines specify using 3 treatment
groups plus a control. Effects were observed at both doses and a NOAEL could not be
determined.
Continued on next page ...
Page 152 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 6 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Nutritional/Metabolic (Clinical signs); Neurological/Behavioral (Clinical signs);
Outcome(s):
Reported Health Nutritional/Metabolic (Clinical signs): Body weights; Neurological/Behavioral (Clinical signs): Serum cholinesterase activity (special study 16-day and
Effect(s): 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy, histopathology (brain);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 12:
Exposure Route and Method
High
All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Medium
All Outcomes: The study used male and female F344/N rats. The test animal source
(Harlan industries) and age at the start of the study (8-10 weeks old) were reported.
Although initial animal body weights for the 16-day and 16-week studies were reported,
the initial body weights for the 2-year study are not reported. Body weight data begin
after 1 week of dosing.
Metric 14:
Adequacy and Consistency of Animal
Low
All Outcomes: The number of animals per cage (5/cage) was reported. According to
Husbandry Conditions
NTP guidelines for chronic/carcinogenicity studies, male rats should only be housed up
to 3 per cage. Food and water were provided ad libiutm. Animal room environments
(temperature, humidity, lighting were reported. The humidity ranged considerably from
15% to 84% . This deviates from NTP guidelines which state humidity should not be
below 35% or above 65% . Similarly, the temperature range was reported to be between
60 and 86 degrees F. NTP guidelines state that the temperatures shall not be below 69 or
above 75 degrees F, with minimal fluctuations. It is unclear whether these deviations had
a significant impact on the study results.
Metric 15:
Number of Animals per Group
Medium
Nutritional/Metabolic (Clinical signs): The study methods specify 50/sex/group which
is consistent with NTP guidelines for a chronic/carcinogenicity study, plus an extra 10/
sex/group for an interim sacrifice.; Neurological/Behavioral (Clinical signs): The study
methods specify 50/sex/group which is consistent with NTP guidelines for a chronic/
carcinogenicity study. An extra 10/sex/group were added for an interim sacrifice at 66
weeks.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
Nutritional/Metabolic (Clinical signs): The outcome assessment methodology was de-
scribed and was sensitive to the outcome of interest. Body weights were measured ini-
tially, then weekly through week 13, and monthly after week 13. Weights were recorded
at 3-4 week intervals for the last 3 months.; Neurological/Behavioral (Clinical signs):
A limited number of organs were weighed (including the brain) at the 66-week interim
sacrifice, and animals were subjected to gross necropsy and detailed histopathology.
Only histopathology was conducted at the 2-yr terminal sacrifice. The methods for these
endpoints were described and were sensitive to the outcomes of interest.
Metric 17:
Consistency of Outcome Assessment
High
All Outcomes: The same protocol was applied to animals from all groups, and animals
were consistently assessed for the outcomes of interest.
Continued on next page ...
Page 153 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 6 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Nutritional/Metabolic (Clinical signs); Neurological/Behavioral (Clinical signs);
Outcome(s):
Reported Health Nutritional/Metabolic (Clinical signs): Body weights; Neurological/Behavioral (Clinical signs): Serum cholinesterase activity (special study 16-day and
Effect(s): 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy, histopathology (brain);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Medium Nutritional/Metabolic (Clinical signs): The number of animals sampled (n) is not ex-
plicitly shown on the growth curve figures or body weight tables. The table does report
the number of surviving animals at each timepoint. It is assumed the body weights were
measured for all of the surviving animals shown.; Neurological/Behavioral (Clinical
signs): Sampling was adequate for all outcomes. Organs were weighed from all sur-
viving animals at the interim sacrifice, and histopathology was purportedly conducted
on all animals from all groups both at the interim and terminal sacrifices, but interim
histopathology data were not reported, so sampling cannot be verified.
N/A All Outcomes: Blinding is not necessary because this outcome of interest is either not
subjective in nature, or blinding is not required (e.g., initial histopathology).
High Nutritional/Metabolic (Clinical signs): The negative control responses were reported and
were adequate.; Neurological/Behavioral (Clinical signs): The organ weights and non-
neoplastic lesions incidences of negative controls (main group animals) were reported
and were adequate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
High All Outcomes: No confounding variables in the test design and procedures were identi-
fied. The study did not measure food or water intake, but this was not a dietary or drink-
ing water study, and these endpoints are not required for this study type according to
NTP. There were no significant body weight changes that were suggestive of palatability
issues.
Medium All Outcomes: Gavage-related deaths were noted in 4 controls (all males), 4 animals
at 44 mg/kg-day (1 male, 3 females), and 4 at 88 mg/kg-day (all females). There were
also 3 accidental deaths; details were only provided for one high-dose male that was
inadvertently killed at the 66-week interim sacrifice. The small number of deaths not
related to exposure is not expected to have a significant impact on the study results.
High Nutritional/Metabolic (Clinical signs): Statistical methods were adequately described
and were appropriate for the datasets. Statistical significance was shown where appro-
priate.; Neurological/Behavioral (Clinical signs): Statistical methods were adequately
described and were appropriate for the datasets. Statistical significance was shown
where appropriate and quantitative data/incidences were provided for the main group
animals allowing for independent statistical analysis.
Continued on next page ...
Page 154 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 6 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Nutritional/Metabolic (Clinical signs); Neurological/Behavioral (Clinical signs);
Outcome(s):
Reported Health Nutritional/Metabolic (Clinical signs): Body weights; Neurological/Behavioral (Clinical signs): Serum cholinesterase activity (special study 16-day and
Effect(s): 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy, histopathology (brain);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 24: Reporting of Data
Low Nutritional/Metabolic (Clinical signs): Groth curves and body weight tables were pro-
vided. The data were presented as means in the absence of measures of variance. The
study indicates that initial body weights were measured, but the body weight data tables
start after 1 week of exposure.; Neurological/Behavioral (Clinical signs): Organ weight
data from the 66-week interim sacrifice were presented quantitatively and reported as
means ± SEM. Incidence data of non-neoplastic lesions from the main group animals
at terminal sacrifice were adequately reported, although measures of severity were not
included. The methods suggest that histopathology was also conducted on animals sacri-
ficed at 66 weeks, but no quantitative data were provided. A brief description of lesions
in the brain was provided in the text but did not distinguish by group and significance
was not reported.
Overall Quality Determination
High
Page 155 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 28
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Hepatic/Liver (Clinical signs); Renal/Kidney (Clinical signs);
Outcome(s):
Reported Health Hepatic/Liver (Clinical signs): Liver weights, gross necropsy histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine amino-
Effect(s): transferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney (Clinical signs): Serum chemistry (BUN, creatinine), organ
weights, gross necropsy, histopathology (kidney, bladder);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
High All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
High All Outcomes: Animals were dosed with 0, 44, or 88 mg/kg/day, 5 days per week.
Doses were selected based on a subchronic study. Dose formulations were analyzed
at approximately 8-week intervals by gas chromatography, and remained within 10% of
the target concentrations throughout the course of the study. The target and measured
concentrations in the solutions (mg/mL) were reported.
High All Outcomes: Animals were dosed 5 days per week for two years. The exposure fre-
quency and duration are consistent with NTP guidelines.
Continued on next page ...
Page 156 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 28
Domain
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Hepatic/Liver (Clinical signs); Renal/Kidney (Clinical signs);
Outcome(s):
Reported Health Hepatic/Liver (Clinical signs): Liver weights, gross necropsy histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine amino-
Effect(s): transferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney (Clinical signs): Serum chemistry (BUN, creatinine), organ
weights, gross necropsy, histopathology (kidney, bladder);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Metric
Rating
Comments
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Low All Outcomes: This 2-year study only included two treatment groups and a control.
Although the authors justified the doses used, NTP guidelines specify using 3 treatment
groups plus a control. Effects were observed at both doses and a NOAEL could not be
determined.
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Medium
Low
Metric 15: Number of Animals per Group
Medium
All Outcomes: The study used male and female F344/N rats. The test animal source
(Harlan industries) and age at the start of the study (8-10 weeks old) were reported.
Although initial animal body weights for the 16-day and 16-week studies were reported,
the initial body weights for the 2-year study are not reported. Body weight data begin
after 1 week of dosing.
All Outcomes: The number of animals per cage (5/cage) was reported. According to
NTP guidelines for chronic/carcinogenicity studies, male rats should only be housed up
to 3 per cage. Food and water were provided ad libiutm. Animal room environments
(temperature, humidity, lighting were reported. The humidity ranged considerably from
15% to 84% . This deviates from NTP guidelines which state humidity should not be
below 35% or above 65% . Similarly, the temperature range was reported to be between
60 and 86 degrees F. NTP guidelines state that the temperatures shall not be below 69 or
above 75 degrees F, with minimal fluctuations. It is unclear whether these deviations had
a significant impact on the study results.
All Outcomes: The study methods specify 50/sex/group which is consistent with NTP
guidelines for a chronic/carcinogenicity study. An extra 10/sex/group were added for an
interim sacrifice at 66 weeks.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology High Hepatic/Liver (Clinical signs): Serum chemistry measurements and a limited number
of organs were weighed at the 66-week interim sacrifice, and animals were subjected
to gross necropsy and detailed histopathology. Only histopathology was conducted at
the 2-yr terminal sacrifice. The methods for these endpoints were described and were
sensitive to the outcomes of interest.; Renal/Kidney (Clinical signs): Serum chemistry
measurements and a limited number of organs were weighed at the 66-week interim sac-
rifice, and these animals were subjected to gross necropsy and detailed histopathology.
Only histopathology was conducted at the 2-yr terminal sacrifice. The methods for these
endpoints were described and were sensitive to the outcomes of interest.
Continued on next page ...
Page 157 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Hepatic/Liver (Clinical signs); Renal/Kidney (Clinical signs);
Outcome(s):
Reported Health Hepatic/Liver (Clinical signs): Liver weights, gross necropsy histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine amino-
Effect(s): transferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney (Clinical signs): Serum chemistry (BUN, creatinine), organ
weights, gross necropsy, histopathology (kidney, bladder);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 17:
Consistency of Outcome Assessment
High
All Outcomes: The same protocol was applied to animals from all groups, and animals
were consistently assessed for the outcomes of interest.
Metric 18:
Sampling Adequacy
Medium
Hepatic/Liver (Clinical signs): Sampling was adequate for most outcomes. Organs were
weighed from all surviving animals at the interim sacrifice, and histopathology was
purportedly conducted on all animals from all groups both at the interim and terminal
sacrifices, but interim serum chemistry and histopathology data were not reported, so
sampling cannot be verified.; Renal/Kidney (Clinical signs): Sampling was adequate for
all outcomes. Organs were weighed from all surviving animals at the interim sacrifice,
and histopathology was purportedly conducted on all animals from all groups both at the
interim and terminal sacrifices. Serum chemistry and interim histopathology data were
not reported, so sampling cannot be verified.
Metric 19:
Blinding of Assessors
N/A
All Outcomes: Blinding is not necessary because this outcome of interest is either not
subjective in nature, or blinding is not required (e.g., initial histopathology).
Metric 20:
Negative Control Response
Medium
Hepatic/Liver (Clinical signs): The organ weights and non-neoplastic lesions incidences
of negative controls (main group animals) were reported and were adequate. The nega-
tive control responses for serum chemistry and for histopathology at the 66-week interim
sacrifice were not provided.; Renal/Kidney (Clinical signs): The organ weights and non-
neoplastic lesions incidences of negative controls (main group animals) were reported
and were adequate. The adequacy of biological responses of the negative controls for
serum chemistry endpoints or for histopathology at the 66-week interim sacrifice cannot
be determined because quantitative data were not provided.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
High All Outcomes: No confounding variables in the test design and procedures were identi-
fied. The study did not measure food or water intake, but this was not a dietary or drink-
ing water study, and these endpoints are not required for this study type according to
NTP. There were no significant body weight changes that were suggestive of palatability
issues.
Medium All Outcomes: Gavage-related deaths were noted in 4 controls (all males), 4 animals
at 44 mg/kg-day (1 male, 3 females), and 4 at 88 mg/kg-day (all females). There were
also 3 accidental deaths; details were only provided for one high-dose male that was
inadvertently killed at the 66-week interim sacrifice. The small number of deaths not
related to exposure is not expected to have a significant impact on the study results.
High All Outcomes: Statistical methods were adequately described and were appropriate
for the datasets. Statistical significance was shown where appropriate and quantitative
data/incidences were provided for the main group animals allowing for independent
statistical analysis.
Continued on next page ...
Page 158 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 7 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Hepatic/Liver (Clinical signs); Renal/Kidney (Clinical signs);
Outcome(s):
Reported Health Hepatic/Liver (Clinical signs): Liver weights, gross necropsy histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine amino-
Effect(s): transferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney (Clinical signs): Serum chemistry (BUN, creatinine), organ
weights, gross necropsy, histopathology (kidney, bladder);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 24: Reporting of Data
Low Hepatic/Liver (Clinical signs): Organ weight data from the 66-week interim sacrifice
were presented quantitatively and reported as means ± SEM. Incidence data of non-
neoplastic lesions from the main group animals at terminal sacrifice were adequately
reported, although measures of severity were not included. The methods suggest that
histopathology was also conducted on animals sacrificed at 66 weeks, but no quantitative
data were provided. The text only indicated that observed lesions (other than those in the
brain) were considered incidental and unrelated to treatment. Exposure-related serum
chemistry results were described in the text; significance was noted.; Renal/Kidney
(Clinical signs): Organ weight data from the 66-week interim sacrifice were presented
quantitatively and reported as means ± SEM. Incidence data of non-neoplastic lesions
from the main group animals at terminal sacrifice were adequately reported, although
measures of severity were not included. The methods suggest that histopathology was
also conducted on animals sacrificed at 66 weeks, but no quantitative data were pro-
vided. The text only indicated that observed lesions (other than those in the brain) were
considered incidental and unrelated to treatment. Results for all serum chemistry end-
points were not reported, only a single change for a liver enzyme was mentioned in the
text.
Overall Quality Determination
High
Page 159 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
N/A All Outcomes: Positive controls are not required for this study type.
Medium All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test
Substance
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
High All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
High All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
High All Outcomes: Animals were dosed with 0, 44, or 88 mg/kg/day, 5 days per week.
Doses were selected based on a subchronic study. Dose formulations were analyzed
at approximately 8-week intervals by gas chromatography, and remained within 10% of
the target concentrations throughout the course of the study. The target and measured
concentrations in the solutions (mg/mL) were reported.
Continued on next page ...
Page 160 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10:
Exposure Frequency and Duration
High
All Outcomes: Animals were dosed 5 days per week for two years. The exposure fre-
quency and duration are consistent with NTP guidelines.
Metric 11:
Number of Exposure Groups and
Low
All Outcomes: This 2-year study only included two treatment groups and a control.
Dose/Concentration Spacing
Although the authors justified the doses used, NTP guidelines specify using 3 treatment
groups plus a control. Effects were observed at both doses and a NOAEL could not be
determined.
Metric 12:
Exposure Route and Method
High
All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Medium
Low
Metric 15: Number of Animals per Group
Medium
All Outcomes: The study used male and female F344/N rats. The test animal source
(Harlan industries) and age at the start of the study (8-10 weeks old) were reported.
Although initial animal body weights for the 16-day and 16-week studies were reported,
the initial body weights for the 2-year study are not reported. Body weight data begin
after 1 week of dosing.
All Outcomes: The number of animals per cage (5/cage) was reported. According to
NTP guidelines for chronic/carcinogenicity studies, male rats should only be housed up
to 3 per cage. Food and water were provided ad libiutm. Animal room environments
(temperature, humidity, lighting were reported. The humidity ranged considerably from
15% to 84% . This deviates from NTP guidelines which state humidity should not be
below 35% or above 65% . Similarly, the temperature range was reported to be between
60 and 86 degrees F. NTP guidelines state that the temperatures shall not be below 69 or
above 75 degrees F, with minimal fluctuations. It is unclear whether these deviations had
a significant impact on the study results.
All Outcomes: The study methods specify 50/sex/group which is consistent with NTP
guidelines for a chronic/carcinogenicity study. An extra 10/sex/group were added for an
interim sacrifice at 66 weeks.
Domain 5: Outcome Assessment
Continued on next page .
Page 161 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Metric 16: Outcome Assessment Methodology High Immune/Hematological: Hematological analysis was done on animals from the 66-
week interim sacrifice, and these animals were subjected to gross necropsy and detailed
histopathology. Only histopathology was conducted at the 2-yr terminal sacrifice. The
methods for these endpoints were described and were sensitive to the outcomes of in-
terest.; Reproductive/Developmental: Animals from the 66-week interim sacrifice were
subjected to gross necropsy and detailed histopathology. Only histopathology was con-
ducted at the 2-yr terminal sacrifice. The methods for these endpoints were described
and were sensitive to the outcomes of interest.; Cardiovascular: Animals from the 66-
week interim sacrifice were subjected to gross necropsy and detailed histopathology.
Only histopathology was conducted at the 2-yr terminal sacrifice. The methods for these
endpoints were described and were sensitive to the outcomes of interest.; Gastrointesti-
nal: Animals from the 66-week interim sacrifice were subjected to gross necropsy and
detailed histopathology. Only histopathology was conducted at the 2-yr terminal sacri-
fice. The methods for these endpoints were described and were sensitive to the outcomes
of interest.; Thyroid: Animals from the 66-week interim sacrifice were subjected to
gross necropsy and detailed histopathology. Only histopathology was conducted at the
2-yr terminal sacrifice. The methods for these endpoints were described and were sen-
sitive to the outcomes of interest.; Skin/Connective Tissue: Animals from the 66-week
interim sacrifice were subjected to gross necropsy and detailed histopathology. Only
histopathology was conducted at the 2-yr terminal sacrifice. The methods for these end-
points were described and were sensitive to the outcomes of interest.; Musculoskeletal:
Animals from the 66-week interim sacrifice were subjected to gross necropsy and de-
tailed histopathology. Only histopathology was conducted at the 2-yr terminal sacrifice.
The methods for these endpoints were described and were sensitive to the outcomes of
interest.; Ocular/Sensory: Animals from the 66-week interim sacrifice were subjected
to gross necropsy and detailed histopathology. Only histopathology was conducted at
the 2-yr terminal sacrifice. The methods for these endpoints were described and were
sensitive to the outcomes of interest.
Continued on next page ...
Page 162 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
High Continued, metric comment- Lung/Respiratory: Animals from the 66-week interim sacri-
fice were subjected to gross necropsy and detailed histopathology. Only histopathology
was conducted at the 2-yr terminal sacrifice. The methods for these endpoints were
described and were sensitive to the outcomes of interest.; Endocrine (Endocrine): Ani-
mals from the 66-week interim sacrifice were subjected to gross necropsy and detailed
histopathology. Only histopathology was conducted at the 2-yr terminal sacrifice. The
methods for these endpoints were described and were sensitive to the outcomes of inter-
est.
High All Outcomes: The same protocol was applied to animals from all groups, and animals
were consistently assessed for the outcomes of interest.
Continued on next page ...
Page 163 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Metric 18: Sampling Adequacy Medium Immune/Hematological: Histopathology was purportedly conducted on all animals from
all groups both at the interim and terminal sacrifices, but interim histopathology data
were not reported, so sampling cannot be verified. Similarly, sampling cannot be verified
for hematology results which were qualitatively reported as being negative in the text.;
Reproductive/Developmental: Histopathology was purportedly conducted on all animals
from all groups both at the interim and terminal sacrifices, but interim histopathology
data were not reported, so sampling cannot be verified. Sampling was adequate for the
terminal histopathology.; Cardiovascular: Histopathology was purportedly conducted
on all animals from all groups both at the interim and terminal sacrifices, but interim
histopathology data were not reported, so sampling cannot be verified. Sampling was
adequate for the terminal histopathology.; Gastrointestinal: Histopathology was purport-
edly conducted on all animals from all groups both at the interim and terminal sacri-
fices, but interim histopathology data were not reported, so sampling cannot be verified.
Sampling was adequate for the terminal histopathology.; Thyroid: Histopathology was
purportedly conducted on all animals from all groups both at the interim and terminal
sacrifices, but interim histopathology data were not reported, so sampling cannot be ver-
ified. Sampling was adequate for the terminal histopathology.; Skin/Connective Tissue:
Histopathology was purportedly conducted on all animals from all groups both at the
interim and terminal sacrifices, but interim histopathology data were not reported, so
sampling cannot be verified. Sampling was adequate for the terminal histopathology.;
Musculoskeletal: Histopathology was purportedly conducted on all animals from all
groups both at the interim and terminal sacrifices, but interim histopathology data were
not reported, so sampling cannot be verified. Sampling was adequate for the terminal
histopathology.; Ocular/Sensory: Histopathology was purportedly conducted on all ani-
mals from all groups both at the interim and terminal sacrifices, but interim histopathol-
ogy data were not reported, so sampling cannot be verified. Sampling was adequate for
the terminal histopathology.; Lung/Respiratory: Histopathology was purportedly con-
ducted on all animals from all groups both at the interim and terminal sacrifices, but
interim histopathology data were not reported, so sampling cannot be verified. Sampling
was adequate for the terminal histopathology.; Endocrine (Endocrine): Histopathology
was purportedly conducted on all animals from all groups both at the interim and termi-
nal sacrifices, but interim histopathology data were not reported, so sampling cannot be
verified. Sampling was adequate for the terminal histopathology.
Continued on next page ...
Page 164 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 19: Blinding of Assessors
N/A Immune/Hematological: Blinding is not necessary because this outcome of interest is
either not subjective in nature, or blinding is not required (e.g., initial histopathology).;
Reproductive/Developmental: Blinding is not necessary because blinding is not required
for initial histopathology examinations.; Cardiovascular: Blinding is not necessary be-
cause blinding is not required for initial histopathology examinations.; Gastrointestinal:
Blinding is not necessary because blinding is not required for initial histopathology ex-
aminations.; Thyroid: Blinding is not necessary because blinding is not required for
initial histopathology examinations.; Skin/Connective Tissue: Blinding is not necessary
because blinding is not required for initial histopathology examinations.; Musculoskele-
tal: Blinding is not necessary because blinding is not required for initial histopathol-
ogy examinations.; Ocular/Sensory: Blinding is not necessary because blinding is not
required for initial histopathology examinations.; Lung/Respiratory: Blinding is not
necessary because blinding is not required for initial histopathology examinations.;
Endocrine (Endocrine): Blinding is not necessary because blinding is not required for
initial histopathology examinations.
Continued on next page ...
Page 165 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Metric 20: Negative Control Response Medium Immune/Hematological: The biological responses of the negative control animals from
the interim sacrifice (hematology and histopathology) were not reported. Non-neoplastic
lesions incidences of negative controls (main group animals) were reported and were ad-
equate.; Reproductive/Developmental: The biological responses of the negative control
animals from the interim sacrifice (histopathology) were not reported. Non-neoplastic
lesions incidences of negative controls from the main group animals were reported and
were adequate.; Cardiovascular: The biological responses of the negative control an-
imals from the interim sacrifice (histopathology) were not reported. Non-neoplastic
lesions incidences of negative controls from the main group animals were reported and
were adequate.; Gastrointestinal: The biological responses of the negative control an-
imals from the interim sacrifice (histopathology) were not reported. Non-neoplastic
lesions incidences of negative controls from the main group animals were reported and
were adequate.; Thyroid: The biological responses of the negative control animals from
the interim sacrifice (histopathology) were not reported. Non-neoplastic lesions inci-
dences of negative controls from the main group animals were reported and were ade-
quate.; Skin/Connective Tissue: The biological responses of the negative control animals
from the interim sacrifice (histopathology) were not reported. Non-neoplastic lesions
incidences of negative controls from the main group animals were reported and were
adequate.; Musculoskeletal: The biological responses of the negative control animals
from the interim sacrifice (histopathology) were not reported. Non-neoplastic lesions
incidences of negative controls from the main group animals were reported and were
adequate.; Ocular/Sensory: The biological responses of the negative control animals
from the interim sacrifice (histopathology) were not reported. Non-neoplastic lesions
incidences of negative controls from the main group animals were reported and were
adequate.; Lung/Respiratory: The biological responses of the negative control animals
from the interim sacrifice (histopathology) were not reported. Non-neoplastic lesions
incidences of negative controls from the main group animals were reported and were
adequate.; Endocrine (Endocrine): The biological responses of the negative control an-
imals from the interim sacrifice (histopathology) were not reported. Non-neoplastic
lesions incidences of negative controls from the main group animals were reported and
were adequate.
Domain 6: Confounding / Variable Control
Continued on next page ...
Page 166 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 21: Confounding Variables in Test Design High
and Procedures
Metric 22: Health Outcomes Unrelated to Medium
Exposure
All Outcomes: No confounding variables in the test design and procedures were identi-
fied. The study did not measure food or water intake, but this was not a dietary or drink-
ing water study, and these endpoints are not required for this study type according to
NTP. There were no significant body weight changes that were suggestive of palatability
issues.
All Outcomes: Gavage-related deaths were noted in 4 controls (all males), 4 animals
at 44 mg/kg-day (1 male, 3 females), and 4 at 88 mg/kg-day (all females). There were
also 3 accidental deaths; details were only provided for one high-dose male that was
inadvertently killed at the 66-week interim sacrifice. The small number of deaths not
related to exposure is not expected to have a significant impact on the study results.
Continued on next page ...
Page 167 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Metric 23: Data Presentation and Analysis Low Immune/Hematological: Statistical methods were adequately described and were ap-
propriate for the datasets. Statistical significance was shown and quantitative data/
incidences were provided for the main group animals allowing for independent statis-
tical analysis. However, histopathology and hematology data from the interim sacrifices
were not provided. Negative findings were generally described, but the lack of statis-
tical significance wasn't specified and these data cannot be independently analyzed.;
Reproductive/Developmental: Statistical methods for determining incidences and tests
for pairwise comparisons and trends were reported and were appropriate for the datasets.
The text reports that lesions identified during the 66-week interim sacrifice were con-
sidered to be incidental. It is unclear if these data were statistically analyzed, and the
data were not provided for an independent analysis. Quantitative histopathology data
from the terminal sacrifice was reported.; Cardiovascular: Statistical methods for de-
termining incidences and tests for pairwise comparisons and trends were reported and
were appropriate for the datasets. The text reports that lesions identified during the 66-
week interim sacrifice were considered to be incidental. It is unclear if these data were
statistically analyzed, and the data were not provided for an independent analysis. Quan-
titative histopathology data from the terminal sacrifice was reported.; Gastrointestinal:
Statistical methods for determining incidences and tests for pairwise comparisons and
trends were reported and were appropriate for the datasets. The text reports that lesions
identified during the 66-week interim sacrifice were considered to be incidental. It is
unclear if these data were statistically analyzed, and the data were not provided for an
independent analysis. Quantitative histopathology data from the terminal sacrifice was
reported.; Thyroid: Statistical methods for determining incidences and tests for pairwise
comparisons and trends were reported and were appropriate for the datasets. The text
reports that lesions identified during the 66-week interim sacrifice were considered to
be incidental. It is unclear if these data were statistically analyzed, and the data were
not provided for an independent analysis. Quantitative histopathology data from the
terminal sacrifice was reported.; Skin/Connective Tissue: Statistical methods for deter-
mining incidences and tests for pairwise comparisons and trends were reported and were
appropriate for the datasets. The text reports that lesions identified during the 66-week
interim sacrifice were considered to be incidental. It is unclear if these data were statisti-
cally analyzed, and the data were not provided for an independent analysis. Quantitative
histopathology data from the terminal sacrifice was reported.
Continued on next page ...
Page 168 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Metric 23: Data Presentation and Analysis Low Continued metric comment- Musculoskeletal: Statistical methods for determining inci-
dences and tests for pairwise comparisons and trends were reported and were appropri-
ate for the datasets. The text reports that lesions identified during the 66-week interim
sacrifice were considered to be incidental. It is unclear if these data were statistically
analyzed, and the data were not provided for an independent analysis. Quantitative
histopathology data from the terminal sacrifice was reported.; Ocular/Sensory: Statisti-
cal methods for determining incidences and tests for pairwise comparisons and trends
were reported and were appropriate for the datasets. The text reports that lesions identi-
fied during the 66-week interim sacrifice were considered to be incidental. It is unclear
if these data were statistically analyzed, and the data were not provided for an indepen-
dent analysis. Quantitative histopathology data from the terminal sacrifice was reported.;
Lung/Respiratory: Statistical methods for determining incidences and tests for pairwise
comparisons and trends were reported and were appropriate for the datasets. The text
reports that lesions identified during the 66-week interim sacrifice were considered to
be incidental. It is unclear if these data were statistically analyzed, and the data were
not provided for an independent analysis. Quantitative histopathology data from the
terminal sacrifice was reported.; Endocrine (Endocrine): Statistical methods for deter-
mining incidences and tests for pairwise comparisons and trends were reported and were
appropriate for the datasets. The text reports that lesions identified during the 66-week
interim sacrifice were considered to be incidental. It is unclear if these data were statisti-
cally analyzed, and the data were not provided for an independent analysis. Quantitative
histopathology data from the terminal sacrifice was reported.
Continued on next page ...
Page 169 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Metric 24: Reporting of Data Low Immune/Hematological: Incidence data of non-neoplastic lesions from the main group
animals at terminal sacrifice were adequately reported, although measures of sever-
ity were not included. The methods suggest that histopathology was also conducted
on animals sacrificed at 66 weeks, but no quantitative data were reported. Only a brief
statement indicating that observed lesions were considered incidental and not related to
treatment. Negative hematology findings were reported qualitatively in the text.; Repro-
ductive/Developmental: Incidence data of non-neoplastic lesions from the main group
animals at terminal sacrifice were adequately reported, although measures of sever-
ity were not included. The methods suggest that histopathology was also conducted
on animals sacrificed at 66 weeks, but no quantitative data were reported. Only a brief
statement indicating that observed lesions were considered incidental and not related to
treatment was provided. Gross findings at either sacrifice time were also not reported.;
Cardiovascular: Incidence data of non-neoplastic lesions from the main group animals
at terminal sacrifice were adequately reported, although measures of severity were not
included. The methods suggest that histopathology was also conducted on animals sac-
rificed at 66 weeks, but no quantitative data were reported. Only a brief statement indi-
cating that observed lesions were considered incidental and not related to treatment was
provided. Gross findings at either sacrifice time were also not reported.; Gastrointesti-
nal: Incidence data of non-neoplastic lesions from the main group animals at terminal
sacrifice were adequately reported, although measures of severity were not included.
The methods suggest that histopathology was also conducted on animals sacrificed at
66 weeks, but no quantitative data were reported. Only a brief statement indicating that
observed lesions were considered incidental and not related to treatment was provided.
Gross findings at either sacrifice time were also not reported.; Thyroid: Incidence data
of non-neoplastic lesions from the main group animals at terminal sacrifice were ade-
quately reported, although measures of severity were not included. The methods suggest
that histopathology was also conducted on animals sacrificed at 66 weeks, but no quan-
titative data were reported. Only a brief statement indicating that observed lesions were
considered incidental and not related to treatment was provided. Gross findings at either
sacrifice time were also not reported.
Continued on next page ...
Page 170 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 24: Reporting of Data
Low Continued, metric comment- Skin/Connective Tissue: Incidence data of non-neoplastic
lesions from the main group animals at terminal sacrifice were adequately reported,
although measures of severity were not included. The methods suggest that histopathol-
ogy was also conducted on animals sacrificed at 66 weeks, but no quantitative data were
reported. Only a brief statement indicating that observed lesions were considered inci-
dental and not related to treatment was provided. Gross findings at either sacrifice time
were also not reported.; Musculoskeletal: Incidence data of non-neoplastic lesions from
the main group animals at terminal sacrifice were adequately reported, although mea-
sures of severity were not included. The methods suggest that histopathology was also
conducted on animals sacrificed at 66 weeks, but no quantitative data were reported.
Only a brief statement indicating that observed lesions were considered incidental and
not related to treatment was provided. Gross findings at either sacrifice time were also
not reported.; Ocular/Sensory: Incidence data of non-neoplastic lesions from the main
group animals at terminal sacrifice were adequately reported, although measures of
severity were not included. The methods suggest that histopathology was also conducted
on animals sacrificed at 66 weeks, but no quantitative data were reported. Only a brief
statement indicating that observed lesions were considered incidental and not related to
treatment was provided. Gross findings at either sacrifice time were also not reported.;
Lung/Respiratory: Incidence data of non-neoplastic lesions from the main group ani-
mals at terminal sacrifice were adequately reported, although measures of severity were
not included. The methods suggest that histopathology was also conducted on animals
sacrificed at 66 weeks, but no quantitative data were reported. Only a brief statement
indicating that observed lesions were considered incidental and not related to treatment
was provided. Gross findings at either sacrifice time were also not reported.; Endocrine
(Endocrine): Incidence data of non-neoplastic lesions from the main group animals at
terminal sacrifice were adequately reported, although measures of severity were not
included. The methods suggest that histopathology was also conducted on animals
sacrificed at 66 weeks, but no quantitative data were reported. Only a brief statement
indicating that observed lesions were considered incidental and not related to treatment
was provided. Gross findings at either sacrifice time were also not reported.
Overall Quality Determination
High
Continued on next page .
Page 171 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 8 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Immune/Hematological; Reproductive/Developmental; Cardiovascular; Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/
Sensory; Lung/Respiratory; Endocrine (Endocrine);
Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count),
thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow); Reproductive/Developmental;
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus); Cardio-
vascular: Heart organ weights, gross necropsy, histopathology (heart); Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice
only), large intestines (cecum, colon, rectum), salivary gland, small intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross
necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology
(skeletal muscle, bone); Ocular/Sensory: Gross necropsy, histopathology (harderian gland); Lung/Respiratory: Gross necropsy, histopathology (lung, nose,
trachea); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 2-yrs (104-weeks rats)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Page 172 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 9 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Renal/Kidney; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate
aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney: Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology
(kidney, bladder); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
High All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
High All Outcomes: The doses were clearly reported. Animals were exposed to 0, 175, or
350 mg/kg, 5 days per week. Adjusted or time-weighted average doses in mg/kg-day
were not provided, but can be determined using the data provided. Dose formulations
were analyzed at approximately 8-week intervals by gas chromatography, and remained
within 10% of the target concentrations throughout the course of the study. The target
and measured concentrations in the solutions (mg/mL) were reported.
High All Outcomes: Animals were dosed 5 days per week for two years. The exposure fre-
quency and duration are consistent with NTP guidelines.
Continued on next page ...
Page 173 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 9 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Renal/Kidney; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate
aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney: Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology
(kidney, bladder); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Low All Outcomes: This 2-year study only included two treatment groups and a control.
Although the authors justified the doses used, NTP guidelines specify using 3 treatment
groups plus a control. Effects were observed at both doses and a NOAEL could not be
determined.
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Medium
Low
Metric 15: Number of Animals per Group
Medium
All Outcomes: The study used male and female B6C3F1 mice. The test animal source
(Harlan industries), age at the start of the study (8-9 weeks old) were reported. Although
initial animal body weights for the 16-day and 16-week studies were reported, the initial
body weights for the 2-year study are not reported. Body weight data begin after 1 week
of dosing.
All Outcomes: The number of animals per cage (5/cage) was reported. According to
NTP guidelines for chronic/carcinogenicity studies, male mice should be housed indi-
vidually. Food and water were provided ad libiutm. Animal room environments (tem-
perature, humidity, lighting were reported. The humidity ranged considerably from 15%
to 84% . This deviates from NTP guidelines which state humidity should not be below
35% or above 65% .Similarly, the temperature range was reported to be between 60 and
86 degrees F. NTP guidelines state that the temperatures shall not be below 69 or above
75 degrees F, with minimal fluctuations. It is unclear whether these deviations had an
impact on the study results.
All Outcomes: The study methods specify 50/sex/group which is consistent with NTP
guidelines for a chronic/carcinogenicity study. An extra 10/sex/group were added for an
interim sacrifice at 66 weeks.
Domain 5: Outcome Assessment
Continued on next page .
Page 174 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 9 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Renal/Kidney; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate
aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney: Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology
(kidney, bladder); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
High Hepatic/Liver: The study included interim sacrifices (10/sex/group) at 66-weeks. Select
clinical chemistry and organ weights were recorded and these animals were subjected
to gross necropsy and histopathology. Histopathological examination of non-neoplastic
lesions was also conducted in the main group of animals at the terminal sacrifice. The
outcome assessment methodology was clearly reported and sensitive to the outcomes
of interest.; Renal/Kidney: The study included interim sacrifices (10/sex/group) at 66-
weeks. Select clinical chemistry and organ weights were recorded and these animals
were subjected to gross necropsy and histopathology. Histopathological examination of
non-neoplastic lesions was also conducted in the main group of animals at the terminal
sacrifice. The outcome assessment methodology was clearly reported and sensitive to
the outcomes of interest.; Immune/Hematological: The study included interim sacrifices
(10/sex/group) at 66 weeks. Blood was collected for hematological analysis and these
animals were subjected to gross necropsy and histopathology. Histopathological exami-
nation of non-neoplastic lesions was also conducted in the main group of animals at the
terminal sacrifice. A detailed description of histopathological procedures was provided
and the methods were sensitive to the outcomes of interest.
High All Outcomes: Details of the outcome assessment protocol were reported and the out-
comes were consistently assessed for the groups that were examined.
Medium Hepatic/Liver: Organ weight, serum chemistry, and histopathology data were purport-
edly collected from all surviving animals at the interim sacrifice; however, no quantita-
tive results confirming sample sizes were provided. At both the 66-week and 104-week
terminal sacrifices, histopathological analysis was conducted on tissues from the control
and high-dose animals, except for tissues from the harderian gland, kidney, liver, lung,
and stomach, which were also examined from low-dose animals.; Renal/Kidney: Organ
weight, serum chemistry, and histopathology data were purportedly collected from all
surviving animals at the interim sacrifice; however, no quantitative results confirming
sample sizes were provided. At both the 66-week and 104-week terminal sacrifices,
histopathological analysis was conducted on tissues from the control and high-dose
animals, except for tissues from the harderian gland, kidney, liver, lung, and stomach,
which were also examined from low-dose animals.; Immune/Hematological: It is as-
sumed that blood was collected from all surviving animals at the interim sacrifice, but
since negative hematological results were qualitatively reported in the results, the "n" or
sample size cannot be confirmed. At both the 66-week and 104-week terminal sacrifices,
histopathological analysis was conducted on tissues from the control and high-dose
animals, except for tissues from the harderian gland, kidney, liver, lung, and stomach,
which were also examined from low-dose animals. This is not expected to have a signif-
icant impact on the study results because no significant histopathological changes were
noted for this outcome at the high dose.
Continued on next page ...
Page 175 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 9 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Renal/Kidney; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate
aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney: Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology
(kidney, bladder); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High Hepatic/Liver: The study indicated that all histopathology data were sent to an inde-
pendent quality assessment laboratory and slides, tissue counts, and histotechnique
were evaluated. Additionally, all tumor diagnoses, all tissue sections of the brain, kid-
ney, liver, spleen, and thyroid, and tissues randomly selected from 10% of the animals
were re-examined by a pathologist. It was not specified whether these examinations
were done blinded; however, in any instances where there was a disagreement in di-
agnosis, a Pathology Working Group chairperson, reviewed the slides without prior
knowledge of the dose group, or the previous diagnoses.Other outcomes (organ weights,
clinical chemistry) were not subjective in nature.; Renal/Kidney: The study indicated
that all histopathology data were sent to an independent quality assessment laboratory
and slides, tissue counts, and histotechnique were evaluated. Additionally, all tumor
diagnoses, all tissue sections of the brain, kidney, liver, spleen, and thyroid, and tissues
randomly selected from 10% of the animals were re-examined by a pathologist. It was
not specified whether these examinations were done blinded; however, in any instances
where there was a disagreement in diagnosis, a Pathology Working Group chairper-
son, reviewed the slides without prior knowledge of the dose group, or the previous
diagnoses. Other outcomes (organ weights, clinical chemistry) were not subjective in
nature.; Immune/Hematological: The study indicated that all histopathology data were
sent to an independent quality assessment laboratory and slides, tissue counts, and his-
totechnique were evaluated. Additionally, all tumor diagnoses, all tissue sections of the
brain, kidney, liver, spleen, and thyroid, and tissues randomly selected from 10% of the
animals were re-examined by a pathologist. It was not specified whether these exami-
nations were done blinded; however, in any instances where there was a disagreement
in diagnosis, a Pathology Working Group chairperson, reviewed the slides without prior
knowledge of the dose group or the previous diagnoses.
Low Hepatic/Liver: Non-neoplastic control data from the main group animals were reported
and the incidences were appropriate. All results from the interim sacrifice were inad-
equately reported, and the appropriateness of the negative control responses cannot be
confirmed.; Renal/Kidney: Non-neoplastic control data from the main group animals
were reported and the incidences were appropriate. All results from the interim sacrifice
were inadequately reported, and the appropriateness of the negative control responses
cannot be confirmed.; Immune/Hematological: Non-neoplastic control data from the
main group animals were reported and the incidences were appropriate. Histopathol-
ogy results from the 66-interim sacrifice were not reported and hematology results were
only qualitatively described. No gross pathological control responses were reported. The
adequacy of the control responses for these endpoints cannot be determined.
Continued on next page ...
Page 176 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 9 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Renal/Kidney; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate
aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney: Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology
(kidney, bladder); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
High All Outcomes: No confounding variables in the test design and procedures were identi-
fied. The study did not measure food or water intake, but this was not a dietary or drink-
ing water study, and these endpoints are not required for this study type according to
NTP. There were no significant body weight changes that were suggestive of palatability
issues.
Medium All Outcomes: Two control and two high-dose male mice, and one control female
mouse, all predesignated for the interim sacrifice died before week 66. The causes of
death were not specified. Overall, several gavage deaths of both sexes were also noted
across groups. These deaths are not expected to have a significant impact on the study
results.
Low Hepatic/Liver: Statistical methods were adequately described for different data types
and were appropriate for the datasets. For some endpoints (organ weights, gross pathol-
ogy, interim histopathology), it is assumed these data were statistically analyzed, but the
data were not reported, or available for an independent review.; Renal/Kidney: Statisti-
cal methods were adequately described for different data types and were appropriate for
the datasets. For some endpoints (organ weights, gross pathology, interim histopathol-
ogy), it is assumed these data were statistically analyzed, but the data were not reported
or available for an independent review.; Immune/Hematological: Statistical methods
were adequately described for various data types and were appropriate for the datasets.
The study did not provide data enabling an independent statistical analysis for several
endpoints (e.g., hematology, interim histopathology),
Low Hepatic/Liver: Incidence data of non-neoplastic lesions from the main group animals
were adequately reported, although measures of severity were not included. Histopathol-
ogy and organ weight results from the 66-week interim sacrifice were not reported, and
no results for gross examinations were reported. A qualitative statement reported that
there were "no alterations in clinical chemistry deemed to be related to treatment".; Re-
nal/Kidney: Incidence data of non-neoplastic lesions from the main group animals were
adequately reported, although measures of severity were not included. Organ weight
results from the 66-week interim sacrifice were not reported, and no results for gross
examinations were reported. A qualitative statement reported that there were "no alter-
ations in clinical chemistry deemed to be related to treatment". Interim histopathology
results for this outcome were qualitatively reported in the text.; Immune/Hematological:
Incidence data of non-neoplastic lesions from the main group animals were adequately
reported, although measures of severity were not included. Histopathology results from
the 66-week interim sacrifice were not reported, and no results for gross examinations
were reported. Negative hematology findings were qualitatively reported in the text.
Continued on next page ...
Page 177 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 9 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Hepatic/Liver; Renal/Kidney; Immune/Hematological;
Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate
aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney: Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology
(kidney, bladder); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric
Rating
Comments
Overall Quality Determination
High
Page 178 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 10 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
Metric 2: Test Substance Source High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
Metric 3: Test Substance Purity High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
N/A Positive controls are not required for this study type.
Medium Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
High The doses were clearly reported. Animals were exposed to 0, 175, or 350 mg/kg, 5 days
per week. Adjusted or time-weighted average doses in mg/kg-day were not provided,
but can be determined using the data provided. Dose formulations were analyzed at
approximately 8-week intervals by gas chromatography, and remained within 10% of
the target concentrations throughout the course of the study. The target and measured
concentrations in the solutions (mg/mL) were reported.
High Animals were dosed 5 days per week for two years. The exposure frequency and dura-
tion are consistent with NTP guidelines.
Low This 2-year study only included two treatment groups and a control. Although the au-
thors justified the doses used, NTP guidelines specify using 3 treatment groups plus a
control. Effects were observed at both doses and a NOAEL could not be determined.
Continued on next page ...
Page 179 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 10 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 12:
Exposure Route and Method
High
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4:
Test Animals
Metric 13:
Test Animal Characteristics
Medium
The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (8-9 weeks old) were reported. Although initial animal
body weights for the 16-day and 16-week studies were reported, the initial body weights
for the 2-year study are not reported. Body weight data begin after 1 week of dosing.
Metric 14:
Adequacy and Consistency of Animal
Low
The number of animals per cage (5/cage) was reported. According to NTP guidelines
Husbandry Conditions
for chronic/carcinogenicity studies, male mice should be housed individually. Food and
water were provided ad libitum. Animal room environments (temperature, humidity,
lighting) were reported. The humidity ranged considerably from 15% to 84% . This
deviates from NTP guidelines which state humidity should not be below 35% or above
65% .Similarly, the temperature range was reported to be between 60 and 86 degrees F.
NTP guidelines state that the temperatures shall not be below 69 or above 75 degrees F,
with minimal fluctuations. It is unclear whether these deviations had an impact on the
study results.
Metric 15:
Number of Animals per Group
Medium
The study methods specify 50/sex/group which is consistent with NTP guidelines for a
chronic/carcinogenicity study. An extra 10/sex/group were added for an interim sacrifice
at 66 weeks.
Domain 5:
Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
The outcome assessment methodology was described and sensitive for the outcome
of interest. Body weights were measured initially, then weekly through week 13, and
monthly after week 13. Weights were recorded at 3-4 week intervals for the last 3
months.
Metric 17:
Consistency of Outcome Assessment
High
The same protocol was applied to animals from all groups, and animals were consis-
tently assessed for the outcomes of interest.
Metric 18:
Sampling Adequacy
Medium
There were a few instances noted where the number of animals weighed was less than
the number of animals surviving, and one week (study week 5) where body weights of
male mice were not recorded (an explanation was not provided). The missing informa-
tion is not expected to have a significant impact on the study results.
Metric 19:
Blinding of Assessors
Medium
Blinding was not reported, but blinding is not necessary because this outcome of interest
is either not subjective in nature, or blinding is not required for this endpoint (e.g., initial
histopathology).
Metric 20:
Negative Control Response
High
Negative control body weight and growth data were reported and were adequate.
Domain 6: Confounding / Variable Control
Continued on next page .
Page 180 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 10 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 21:
Confounding Variables in Test Design
and Procedures
High
No confounding variables in the test design and procedures were identified. The study
did not measure food or water intake, but this was not a dietary or drinking water study,
and these endpoints are not required for this study type according to NTP. There were no
significant body weight changes that were suggestive of palatability issues.
Metric 22:
Health Outcomes Unrelated to
Medium
Two control and two high-dose male mice, and one control female mouse, all predes-
Exposure
ignated for the interim sacrifice died before week 66. The causes of death were not
specified. Overall, several gavage deaths of both sexes were also noted across groups.
These deaths are not expected to have a significant impact on the study results.
Metric 23:
Data Presentation and Analysis
High
Statistical methods were adequately described and were appropriate for the datasets.
Statistical significance was shown where appropriate.
Metric 24:
Reporting of Data
Low
Growth curves and body weight tables were provided. The data were presented as means
in the absence of measures of variance. The study indicates that initial body weights
were measured, but the body weight data tables start after 1 week of exposure.
Overall Quality Determination
High
Page 181 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 11 of 28
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Chronic (>91 days) 2-yrs (104 weeks- mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Metric 10:
Metric 11:
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations High
Exposure Frequency and Duration High
Number of Exposure Groups and Low
Dose/Concentration Spacing
Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
The doses were clearly reported. Animals were exposed to 0, 175, or 350 mg/kg, 5 days
per week. Adjusted or time-weighted average doses in mg/kg-day were not provided,
but can be determined using the data provided. Dose formulations were analyzed at
approximately 8-week intervals by gas chromatography, and remained within 10% of
the target concentrations throughout the course of the study. The target and measured
concentrations in the solutions (mg/mL) were reported.
Animals were dosed 5 days per week for two years. The exposure frequency and dura-
tion are consistent with NTP guidelines.
This 2-year study only included two treatment groups and a control. Although the au-
thors justified the doses used, NTP guidelines specify using 3 treatment groups plus a
control. Effects were observed at both doses and a NOAEL could not be determined.
Continued on next page ...
Page 182 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 11 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Chronic (>91 days) 2-yrs (104 weeks- mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 12:
Exposure Route and Method
High
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Medium
Low
Metric 15: Number of Animals per Group
Medium
The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (8-9 weeks old) were reported. Although initial animal
body weights for the 16-day and 16-week studies were reported, the initial body weights
for the 2-year study are not reported. Body weight data begin after 1 week of dosing.
The number of animals per cage (5/cage) was reported. According to NTP guidelines
for chronic/carcinogenicity studies, male mice should be housed individually. Food and
water were provided ad libiutm. Animal room environments (temperature, humidity,
lighting were reported. The humidity ranged considerably from 15% to 84% . This
deviates from NTP guidelines which state humidity should not be below 35% or above
65% .Similarly, the temperature range was reported to be between 60 and 86 degrees F.
NTP guidelines state that the temperatures shall not be below 69 or above 75 degrees F,
with minimal fluctuations. It is unclear whether these deviations had an impact on the
study results.
The study methods specify 50/sex/group which is consistent with NTP guidelines for a
chronic/carcinogenicity study. An extra 10/sex/group were added for an interim sacrifice
at 66 weeks.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Outcome Assessment Methodology
Consistency of Outcome Assessment
Sampling Adequacy
Metric 19: Blinding of Assessors
High The study included interim sacrifices (10/sex/group) at 66-weeks. Select organ weights
were recorded and these animals were subjected to gross necropsy and histopathology.
Histopathological examination of non-neoplastic lesions was also conducted in the main
group of animals at the terminal sacrifice. The outcome assessment methodology was
clearly reported and sensitive to the outcomes of interest.
High Details of the outcome assessment protocol were reported and the outcomes were con-
sistently assessed for the groups that were examined.
Medium Organs were purportedly weighed from all surviving animals at the interim sacrifice;
however, no quantitative organ weight results were reported and sampling adequacy can-
not be confirmed. At both the 66-week and 104-week terminal sacrifices, histopatholog-
ical analysis was conducted on tissues from the control and high-dose animals, except
for tissues from the harderian gland, kidney, liver, lung, and stomach, which were also
examined from low-dose animals.
Medium The study indicated that all histopathology data were sent to an independent quality
assessment laboratory and slides, tissue counts, and histotechnique were evaluated.
Blinding was not reported but is not required for initial histopathology.
Continued on next page ...
Page 183 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 11 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Chronic (>91 days) 2-yrs (104 weeks- mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 20:
Negative Control Response
Low
Non-neoplastic control data from the main group animals were reported and the inci-
dences were appropriate. Gross pathological control responses were not reported. All
results from the interim sacrifice were inadequately reported, and the appropriateness of
the negative control responses cannot be confirmed.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
High No confounding variables in the test design and procedures were identified. The study
did not measure food or water intake, but this was not a dietary or drinking water study,
and these endpoints are not required for this study type according to NTP. There were no
significant body weight changes that were suggestive of palatability issues.
Medium Two control and two high-dose male mice, and one control female mouse, all predes-
ignated for the interim sacrifice died before week 66. The causes of death were not
specified. Overall, several gavage deaths of both sexes were also noted across groups.
These deaths are not expected to have a significant impact on the study results.
Low Statistical methods were adequately described for different data types and were appro-
priate for the datasets. For some endpoints (organ weights, gross pathology, interim
histopathology), it is assumed these data were statistically analyzed, but the data were
not reported, or available for an independent review.
Low Incidence data of non-neoplastic lesions from the main group animals were adequately
reported, although measures of severity were not included. Histopathology results from
the 66-week interim sacrifice were not reported, and no results for gross examinations
were reported. Organ weight data also were not reported.
Overall Quality Determination
High
Page 184 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 12 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Musculoskeletal; Cardiovascular; Skin/Connective Tissue; Endocrine (Endocrine); Thyroid;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Cardiovascular: Heart organ weights, gross necropsy,
histopathology (heart); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pan-
creas, adrenal glands, pituitary glands, parathyroid); Thyroid: Gross necropsy and histopathology (thyroid);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3: Exposure Characterization
Continued on next page .
Page 185 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 12 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Musculoskeletal; Cardiovascular; Skin/Connective Tissue; Endocrine (Endocrine); Thyroid;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Cardiovascular: Heart organ weights, gross necropsy,
histopathology (heart); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pan-
creas, adrenal glands, pituitary glands, parathyroid); Thyroid: Gross necropsy and histopathology (thyroid);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 7:
Preparation and Storage of Test
Substance
Metric 8:
Consistency of Exposure
Administration
High Reproductive/Developmental: Stability studies were conducted. The bulk chemical
was stable for at least 2 weeks in sealed containers at room temperature. Stability was
monitored throughout the study and no degradation was observed. Additionally, the test
solutions (TCEP in corn oil) were also stable for 21 days in the dark at room temper-
ature or open to air and light for 3 hours. For the studies, the dose formulations were
stored at 0-5 degrees C for 2 weeks. Fresh solutions were made every two weeks.; Mus-
culoskeletal: Stability studies were conducted. The bulk chemical was stable for at least
2 weeks in sealed containers at room temperature. Stability was monitored throughout
the study and no degradation was observed. Additionally, the test solutions (TCEP in
corn oil) were also stable for 21 days in the dark at room temperature or open to air and
light for 3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for
2 weeks. Fresh solutions were made every two weeks.; Cardiovascular: Stability studies
were conducted. The bulk chemical was stable for at least 2 weeks in sealed containers
at room temperature. Stability was monitored throughout the study and no degradation
was observed. Additionally, the test solutions (TCEP in corn oil) were also stable for 21
days in the dark at room temperature or open to air and light for 3 hours. For the studies,
the dose formulations were stored at 0-5 degrees C for 2 weeks. Fresh solutions were
made every two weeks; Skin/Connective Tissue: Stability studies were conducted. The
bulk chemical was stable for at least 2 weeks in sealed containers at room temperature.
Stability was monitored throughout the study and no degradation was observed. Addi-
tionally, the test solutions (TCEP in corn oil) were also stable for 21 days in the dark at
room temperature or open to air and light for 3 hours. For the studies, the dose formu-
lations were stored at 0-5 degrees C for 2 weeks. Fresh solutions were made every two
weeks.; Endocrine (Endocrine): Stability studies were conducted. The bulk chemical
was stable for at least 2 weeks in sealed containers at room temperature. Stability was
monitored throughout the study and no degradation was observed. Additionally, the test
solutions (TCEP in corn oil) were also stable for 21 days in the dark at room temper-
ature or open to air and light for 3 hours. For the studies, the dose formulations were
stored at 0-5 degrees C for 2 weeks. Fresh solutions were made every two weeks.; Thy-
roid: Stability studies were conducted. The bulk chemical was stable for at least 2 weeks
in sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
High All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
Continued on next page ...
Page 186 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 12 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Musculoskeletal; Cardiovascular; Skin/Connective Tissue; Endocrine (Endocrine); Thyroid;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Cardiovascular: Heart organ weights, gross necropsy,
histopathology (heart); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pan-
creas, adrenal glands, pituitary glands, parathyroid); Thyroid: Gross necropsy and histopathology (thyroid);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High All Outcomes: The doses were clearly reported. Animals were exposed to 0, 175, or
350 mg/kg, 5 days per week. Adjusted or time-weighted average doses in mg/kg-day
were not provided, but can be determined using the data provided. Dose formulations
were analyzed at approximately 8-week intervals by gas chromatography, and remained
within 10% of the target concentrations throughout the course of the study. The target
and measured concentrations in the solutions (mg/mL) were reported.
High All Outcomes: Animals were dosed 5 days per week for two years. The exposure fre-
quency and duration are consistent with NTP guidelines.
Low All Outcomes: This 2-year study only included two treatment groups and a control.
Although the authors justified the doses used, NTP guidelines specify using 3 treatment
groups plus a control. Effects were observed at both doses and a NOAEL could not be
determined.
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics Medium All Outcomes: The study used male and female B6C3F1 mice. The test animal source
(Harlan industries), age at the start of the study (8-9 weeks old) were reported. Although
initial animal body weights for the 16-day and 16-week studies were reported, the initial
body weights for the 2-year study are not reported. Body weight data begin after 1 week
of dosing.
Continued on next page ...
Page 187 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 5469669 Table: 12 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Musculoskeletal; Cardiovascular; Skin/Connective Tissue; Endocrine (Endocrine); Thyroid;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Cardiovascular: Heart organ weights, gross necropsy,
histopathology (heart); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pan-
creas, adrenal glands, pituitary glands, parathyroid); Thyroid: Gross necropsy and histopathology (thyroid);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric Rating Comments
Metric 14: Adequacy and Consistency of Animal Low Reproductive/Developmental: The number of animals per cage (5/cage) was reported.
Husbandry Conditions According to NTP guidelines for chronic/carcinogenicity studies, male mice should
be housed individually. Food and water were provided ad libitum. Animal room envi-
ronments (temperature, humidity, lighting) were reported. The humidity ranged con-
siderably from 15% to 84% . This deviates from NTP guidelines which state humidity
should not be below 35% or above 65% .Similarly, the temperature range was reported
to be between 60 and 86 degrees F. NTP guidelines state that the temperatures shall not
be below 69 or above 75 degrees F, with minimal fluctuations. It is unclear whether
these deviations had an impact on the study results.; Musculoskeletal: The number
of animals per cage (5/cage) was reported. According to NTP guidelines for chronic/
carcinogenicity studies, male mice should be housed individually. Food and water were
provided ad libiutm. Animal room environments (temperature, humidity, lighting were
reported. The humidity ranged considerably from 15% to 84% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% .Similarly, the
temperature range was reported to be between 60 and 86 degrees F. NTP guidelines
state that the temperatures shall not be below 69 or above 75 degrees F, with minimal
fluctuations. It is unclear whether these deviations had an impact on the study results.;
Cardiovascular: The number of animals per cage (5/cage) was reported. According to
NTP guidelines for chronic/carcinogenicity studies, male mice should be housed indi-
vidually. Food and water were provided ad libiutm. Animal room environments (tem-
perature, humidity, lighting were reported. The humidity ranged considerably from 15%
to 84% . This deviates from NTP guidelines which state humidity should not be below
35% or above 65% .Similarly, the temperature range was reported to be between 60 and
86 degrees F. NTP guidelines state that the temperatures shall not be below 69 or above
75 degrees F, with minimal fluctuations. It is unclear whether these deviations had an
impact on the study results.; Skin/Connective Tissue: The number of animals per cage
(5/cage) was reported. According to NTP guidelines for chronic/carcinogenicity studies,
male mice should be housed individually. Food and water were provided ad libiutm. An-
imal room environments (temperature, humidity, lighting were reported. The humidity
ranged considerably from 15% to 84% . This deviates from NTP guidelines which state
humidity should not be below 35% or above 65% .Similarly, the temperature range was
reported to be between 60 and 86 degrees F. NTP guidelines state that the temperatures
shall not be below 69 or above 75 degrees F, with minimal fluctuations. It is unclear
whether these deviations had an impact on the study results.
Continued on next page ...
Page 188 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 12 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Musculoskeletal; Cardiovascular; Skin/Connective Tissue; Endocrine (Endocrine); Thyroid;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Cardiovascular: Heart organ weights, gross necropsy,
histopathology (heart); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pan-
creas, adrenal glands, pituitary glands, parathyroid); Thyroid: Gross necropsy and histopathology (thyroid);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Low Continued metric comment- Endocrine (Endocrine): The number of animals per cage
(5/cage) was reported. According to NTP guidelines for chronic/carcinogenicity studies,
male mice should be housed individually. Food and water were provided ad libiutm. An-
imal room environments (temperature, humidity, lighting were reported. The humidity
ranged considerably from 15% to 84% . This deviates from NTP guidelines which state
humidity should not be below 35% or above 65% .Similarly, the temperature range was
reported to be between 60 and 86 degrees F. NTP guidelines state that the temperatures
shall not be below 69 or above 75 degrees F, with minimal fluctuations. It is unclear
whether these deviations had an impact on the study results.; Thyroid: The number
of animals per cage (5/cage) was reported. According to NTP guidelines for chronic/
carcinogenicity studies, male mice should be housed individually. Food and water were
provided ad libiutm. Animal room environments (temperature, humidity, lighting were
reported. The humidity ranged considerably from 15% to 84% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% .Similarly, the
temperature range was reported to be between 60 and 86 degrees F. NTP guidelines
state that the temperatures shall not be below 69 or above 75 degrees F, with minimal
fluctuations. It is unclear whether these deviations had an impact on the study results.
Medium All Outcomes: The study methods specify 50/sex/group which is consistent with NTP
guidelines for a chronic/carcinogenicity study. An extra 10/sex/group were added for an
interim sacrifice at 66 weeks.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Outcome Assessment Methodology High
Consistency of Outcome Assessment High
Sampling Adequacy Medium
All Outcomes: The study included interim sacrifices (10/sex/group) at 66-weeks. These
animals were subjected to gross necropsy and histopathology. Histopathological exami-
nation of non-neoplastic lesions was also conducted in the main group of animals at the
terminal sacrifice. A detailed description of histopathological procedures was provided
and the methods were sensitive to the outcomes of interest.
All Outcomes: Details of the outcome assessment protocol were reported and the out-
comes were consistently assessed for the groups that were examined.
All Outcomes: At both the 66-week and 104-week terminal sacrifices, histopathological
analysis was conducted on tissues from the control and high-dose animals, except for
tissues from the harderian gland, kidney, liver, lung, and stomach, which were also ex-
amined from low-dose animals. This is not expected to have a significant impact on the
study results because no histopathological changes were noted for this outcome at the
high dose.
Continued on next page ...
Page 189 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 12 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Musculoskeletal; Cardiovascular; Skin/Connective Tissue; Endocrine (Endocrine); Thyroid;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Cardiovascular: Heart organ weights, gross necropsy,
histopathology (heart); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pan-
creas, adrenal glands, pituitary glands, parathyroid); Thyroid: Gross necropsy and histopathology (thyroid);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Medium All Outcomes: The study indicated that all histopathology data were sent to an indepen-
dent quality assessment laboratory and slides, tissue counts, and histotechnique were
evaluated. Blinding was not reported but is not required for initial histopathology.
Medium Reproductive/Developmental: 98% of control females had hyperplasia in the en-
dometrium and 38% had ovarian cysts. It is assumed that these frequently occur in these
animals. Similar incidences also occurred in the treatment groups.; Musculoskeletal:
Non-neoplastic control data from the main group animals were reported and the in-
cidences were appropriate. Histopathology results from the 66-interim sacrifice were
not reported. Gross pathological control responses were not reported.; Cardiovascular:
Non-neoplastic control data from the main group animals were reported and the inci-
dences were appropriate. Histopathology results from the 66-interim sacrifice were not
reported. Gross pathological control responses were not reported.; Skin/Connective Tis-
sue: Non-neoplastic control data from the main group animals were reported and the
incidences were appropriate. Histopathology results from the 66-interim sacrifice were
not reported. Gross pathological control responses were not reported.; Endocrine (En-
docrine): Non-neoplastic control data from the main group animals were reported and
the incidences were appropriate. Histopathology results from the 66-interim sacrifice
were not reported. Gross pathological control responses were not reported.; Thyroid:
Non-neoplastic control data from the main group animals were reported and the inci-
dences were appropriate. Histopathology results from the 66-interim sacrifice were not
reported. Gross pathological control responses were not reported.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
High All Outcomes: No confounding variables in the test design and procedures were identi-
fied. The study did not measure food or water intake, but this was not a dietary or drink-
ing water study, and these endpoints are not required for this study type according to
NTP. There were no significant body weight changes that were suggestive of palatability
issues.
Medium All Outcomes: Two control and two high-dose male mice, and one control female
mouse, all predesignated for the interim sacrifice died before week 66. The causes of
death were not specified. Overall, several gavage deaths of both sexes were also noted
across groups. These deaths are not expected to have a significant impact on the study
results.
High All Outcomes: Statistical methods were adequately described and were appropriate for
the datasets. Statistical significance was shown where appropriate.
Continued on next page ...
Page 190 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 12 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental; Musculoskeletal; Cardiovascular; Skin/Connective Tissue; Endocrine (Endocrine); Thyroid;
Reproductive/Developmental; Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal
vesicle, testis, uterus); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Cardiovascular: Heart organ weights, gross necropsy,
histopathology (heart); Skin/Connective Tissue: Gross necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pan-
creas, adrenal glands, pituitary glands, parathyroid); Thyroid: Gross necropsy and histopathology (thyroid);
Chronic (>91 days) 2-yrs (104 weeks- mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric
Rating
Comments
Metric 24: Reporting of Data
Low
All Outcomes: Incidence data of non-neoplastic lesions from the main group animals
were adequately reported, although measures of severity were not included. Histopathol-
ogy results from the 66-week interim sacrifice were not reported, and no results for
gross examinations were reported.
Overall Quality Determination
High
Page 191 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 13 of 28
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Unspecified clinical observations (Clinical signs); Unspecified clinical observations (Clinical signs);
Outcome(s):
Reported Health Unspecified clinical observations (Clinical signs): Clinical signs (clinical observations); Unspecified clinical observations (Clinical signs): Clinical signs
Effect(s): (clinical observations);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High Unspecified clinical observations (Clinical signs): The test substance was identified
definitively as tris(2-chloroethyl phosphate) CASRN 115-96-8. A structure was also
provided.; Unspecified clinical observations (Clinical signs): The test substance was
identified definitively as tris(2-chloroethyl phosphate) CASRN 115-96-8. A structure
was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Preparation and Storage of Test
Substance
Consistency of Exposure
Administration
High All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
High All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
Continued on next page ...
Page 192 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 13 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Unspecified clinical observations (Clinical signs); Unspecified clinical observations (Clinical signs);
Outcome(s):
Reported Health Unspecified clinical observations (Clinical signs): Clinical signs (clinical observations); Unspecified clinical observations (Clinical signs): Clinical signs
Effect(s): (clinical observations);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High Unspecified clinical observations (Clinical signs): Animals were dosed with 0, 44, or
88 mg/kg/day, 5 days per week. Doses were selected based on a subchronic study. Dose
formulations were analyzed at approximately 8-week intervals by gas chromatogra-
phy, and remained within 10% of the target concentrations throughout the course of the
study. The target and measured concentrations in the solutions (mg/mL) were reported.;
Unspecified clinical observations (Clinical signs): The doses were clearly reported. Ani-
mals were exposed to 0, 175, or 350 mg/kg, 5 days per week. Adjusted or time-weighted
average doses in mg/kg-day were not provided, but can be determined using the data
provided. Dose formulations were analyzed at approximately 8-week intervals by gas
chromatography, and remained within 10% of the target concentrations throughout the
course of the study. The target and measured concentrations in the solutions (mg/mL)
were reported.
High All Outcomes: Animals were dosed 5 days per week for two years. The exposure fre-
quency and duration are consistent with NTP guidelines.
Low All Outcomes: This 2-year study only included two treatment groups and a control.
Although the authors justified the doses used, NTP guidelines specify using 3 treatment
groups plus a control. Effects were observed at both doses and a NOAEL could not be
determined.
High All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics Medium Unspecified clinical observations (Clinical signs): The study used male and female
F344/N rats. The test animal source (Harlan industries) and age at the start of the study
(8-10 weeks old) were reported. Although initial animal body weights for the 16-day
and 16-week studies were reported, the initial body weights for the 2-year study are not
reported. Body weight data begin after 1 week of dosing.; Unspecified clinical observa-
tions (Clinical signs): The study used male and female B6C3F1 mice. The test animal
source (Harlan industries), age at the start of the study (8-9 weeks old) were reported.
Although initial animal body weights for the 16-day and 16-week studies were reported,
the initial body weights for the 2-year study are not reported. Body weight data begin
after 1 week of dosing.
Continued on next page ...
Page 193 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 13 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Unspecified clinical observations (Clinical signs); Unspecified clinical observations (Clinical signs);
Outcome(s):
Reported Health Unspecified clinical observations (Clinical signs): Clinical signs (clinical observations); Unspecified clinical observations (Clinical signs): Clinical signs
Effect(s): (clinical observations);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Low Unspecified clinical observations (Clinical signs): The number of animals per cage (5/
cage) was reported. According to NTP guidelines for chronic/carcinogenicity studies,
male rats should only be housed up to 3 per cage. Food and water were provided ad li-
biutm. Animal room environments (temperature, humidity, lighting were reported. The
humidity ranged considerably from 15% to 84% . This deviates from NTP guidelines
which state humidity should not be below 35% or above 65% . Similarly, the tempera-
ture range was reported to be between 60 and 86 degrees F. NTP guidelines state that the
temperatures shall not be below 69 or above 75 degrees F, with minimal fluctuations. It
is unclear whether these deviations had a significant impact on the study results.; Un-
specified clinical observations (Clinical signs): The number of animals per cage (5/cage)
was reported. According to NTP guidelines for chronic/carcinogenicity studies, male
mice should be housed individually. Food and water were provided ad libiutm. Ani-
mal room environments (temperature, humidity, lighting were reported. The humidity
ranged considerably from 15% to 84% . This deviates from NTP guidelines which state
humidity should not be below 35% or above 65% .Similarly, the temperature range was
reported to be between 60 and 86 degrees F. NTP guidelines state that the temperatures
shall not be below 69 or above 75 degrees F, with minimal fluctuations. It is unclear
whether these deviations had an impact on the study results.
Medium All Outcomes: The study methods specify 50/sex/group which is consistent with NTP
guidelines for a chronic/carcinogenicity study. An extra 10/sex/group were added for an
interim sacrifice at 66 weeks.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Medium Unspecified clinical observations (Clinical signs): The study indicated that clinical
observations were performed monthly. No additional details were provided, but this
frequency is consistent with NTP guidelines that specify formal examinations should
be conducted every four weeks.; Unspecified clinical observations (Clinical signs): The
study indicated that clinical observations were performed monthly. No additional details
were provided. This frequency is consistent with NTP guidelines that specify formal
examinations every four weeks.
Low Unspecified clinical observations (Clinical signs): Details regarding the execution of the
study protocol for outcome assessment were limited and not sufficient for determining
the consistency of the assessment across groups.; Unspecified clinical observations
(Clinical signs): Because limited details on the protocol for clinical observations were
provided, consistency of assessment across groups cannot be confirmed.
Continued on next page ...
Page 194 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 13 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Unspecified clinical observations (Clinical signs); Unspecified clinical observations (Clinical signs);
Outcome(s):
Reported Health Unspecified clinical observations (Clinical signs): Clinical signs (clinical observations); Unspecified clinical observations (Clinical signs): Clinical signs
Effect(s): (clinical observations);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Low Unspecified clinical observations (Clinical signs): No quantitative data were provided.
The adequacy of the sampling for this outcome cannot be determined.; Unspecified clin-
ical observations (Clinical signs): Results for this endpoint were qualitatively reported
as negative in the text. Although the methods suggest that all animals were observed,
data are not available to confirm the sample size.
Medium Unspecified clinical observations (Clinical signs): Blinding was not reported and clinical
observations can be somewhat subjective in nature.; Unspecified clinical observations
(Clinical signs): The study did not specify whether assessors were blinded for clinical
observations which may be somewhat subjective in nature.
Low Unspecified clinical observations (Clinical signs): The biological responses of the neg-
ative control animals cannot be determined because the data were not reported.; Un-
specified clinical observations (Clinical signs): No quantitative clinical signs data were
reported so the adequacy of the control response cannot be determined.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
High All Outcomes: No confounding variables in the test design and procedures were identi-
fied. The study did not measure food or water intake, but this was not a dietary or drink-
ing water study, and these endpoints are not required for this study type according to
NTP. There were no significant body weight changes that were suggestive of palatability
issues.
Medium Unspecified clinical observations (Clinical signs): Gavage-related deaths were noted in
4 controls (all males), 4 animals at 44 mg/kg-day (1 male, 3 females), and 4 at 88 mg/
kg-day (all females). There were also 3 accidental deaths; details were only provided for
one high-dose male that was inadvertently killed at the 66-week interim sacrifice. The
small number of deaths not related to exposure is not expected to have a significant im-
pact on the study results.; Unspecified clinical observations (Clinical signs): Two control
and two high-dose male mice, and one control female mouse, all predesignated for the
interim sacrifice died before week 66. The causes of death were not specified. Overall,
several gavage deaths of both sexes were also noted across groups. These deaths are not
expected to have a significant impact on the study results.
Low Unspecified clinical observations (Clinical signs): Statistical methods for determining
incidences and tests for pairwise comparisons and trends were reported and were appro-
priate for those types of datasets, but it is unclear if clinical signs data were statistically
analyzed or not, and data were not provided for an independent analysis. The study in-
dicated that there were no clinical signs that were attributed to treatment.; Unspecified
clinical observations (Clinical signs): Statistical methods were adequately described in
general and were appropriate for the datasets. Statistical significance was shown where
appropriate. However, it is not entirely clear whether clinical signs data were statistically
analyzed, and data were not provided for independent review.
Continued on next page ...
Page 195 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 13 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Unspecified clinical observations (Clinical signs); Unspecified clinical observations (Clinical signs);
Outcome(s):
Reported Health Unspecified clinical observations (Clinical signs): Clinical signs (clinical observations); Unspecified clinical observations (Clinical signs): Clinical signs
Effect(s): (clinical observations);
Duration: Chronic (>91 days) 2-yrs (104-weeks rats)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 24: Reporting of Data
High
Unspecified clinical observations (Clinical signs): Negative findings were reported qual-
itatively in the text. No clinical signs were attributed to treatment.; Unspecified clinical
observations (Clinical signs): Negative findings were reported qualitatively in the text.
Overall Quality Determination
High
Page 196 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 14 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks.
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium Animals were dosed with 0, 44, 88, 175, 350, or 700 mg/kg-day, 5 days per week. Time-
adjusted doses in mg/kg-day were not reported, but can be determined using the infor-
mation provided. Dose formulations were analyzed twice during the study by gas chro-
matography and the target and measured concentrations in the solutions (mg/mL) were
reported. The concentrations generally remained with 10% of the target concentration
throughout the course of the study; however, during the second reading, the concentra-
tion used for the second-highest dose group was only 75% of the target.
Medium All mice were dosed 5 days per week for 16 weeks. Generally, the NTP guideline indi-
cates that the subchronic studies should not be more than 97 days. The longer duration
was not justified by the study authors. Dosing 5 days per week for a gavage study is
consistent with NTP guidelines.
Continued on next page ...
Page 197 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 14 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11:
Metric 12:
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
High
High
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9-10 weeks old), and initial body weights were re-
ported and appropriate.
Low The number of animals per cage (5/cage) was reported; however, the NTP guideline
specifies that male mice should always be housed individually. Food and water were
provided ad libiutm. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is not clear
what impact these deviations may have had on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
Metric 17:
Consistency of Outcome Assessment
High
Metric 18:
Sampling Adequacy
High
Metric 19:
Blinding of Assessors
N/A
Metric 20:
Negative Control Response
High
Animals were observed twice daily for morbidity and mortality. The outcome assess-
ment was sensitive and appropriate for the outcome of interest.
Sufficient details of the outcome assessment protocols were provided, and outcome
assessment was carried out consistently across groups.
All animals were sampled for this outcome of interest.
Blinding is not necessary because this outcome of interest is either not subjective in
nature, or blinding is not required (e.g., initial histopathology).
No control animals died.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design High The study did not measure food or water intake, but this was not a dietary or drinking
and Procedures water study, and these endpoints are not required for this study type according to NTP.
There were no significant body weight changes that were suggestive of any palatability
issues (only increased body weights were observed).
Continued on next page ...
Page 198 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 14 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 350 mg/kg group, were instead dosed with 700
mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths
occurred as a result of the dosing error, but two male mice had convulsions and labored
breathing on the third day of overdosing. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 350 mg/kg groups,
respectively.
Metric 23:
Data Presentation and Analysis
High
General statistical methods for evaluating continuous data and incidence data were ade-
quately reported and were appropriate for those data types.
Metric 24:
Reporting of Data
High
Survival data were quantitatively reported and described in the text. The causes (gavage
trauma) and times of death were reported.
Overall Quality Determination
High
Page 199 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 15 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium Animals were dosed with 0, 44, 88, 175, 350, or 700 mg/kg-day, 5 days per week. Time-
adjusted doses in mg/kg-day were not reported, but can be determined using the infor-
mation provided. Dose formulations were analyzed twice during the study by gas chro-
matography and the target and measured concentrations in the solutions (mg/mL) were
reported. The concentrations generally remained with 10% of the target concentration
throughout the course of the study; however, during the second reading, the concentra-
tion used for the second-highest dose group was only 75% of the target.
Medium All mice were dosed 5 days per week for 16 weeks. Generally, the NTP guideline indi-
cates that the subchronic studies should not be more than 97 days. The longer duration
was not justified by the study authors. Dosing 5 days per week for a gavage study is
consistent with NTP guidelines.
Continued on next page ...
Page 200 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 15 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11: Number of Exposure Groups and High
Dose/Concentration Spacing
Metric 12: Exposure Route and Method High
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9-10 weeks old), and initial body weights were re-
ported and appropriate.
Low The number of animals per cage (5/cage) was reported; however, the NTP guideline
specifies that male mice should always be housed individually. Food and water were
provided ad libiutm. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is not clear
what impact these deviations may have had on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
The outcome assessment methods were sensitive and appropriate for the outcome of
interest. Body weights were recorded at study initiation, then weekly thereafter, and
again at termination as per NTP guidelines.
Metric 17:
Consistency of Outcome Assessment
High
Sufficient details of the outcome assessment protocols were provided, and outcome
assessment was carried out consistently across groups.
Metric 18:
Sampling Adequacy
High
All animals were sampled for this outcome of interest.
Metric 19:
Blinding of Assessors
N/A
Blinding is not necessary because this outcome of interest is either not subjective in
nature, or blinding is not required (e.g., initial histopathology).
Metric 20:
Negative Control Response
High
The control responses were reported and were appropriate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design High The study did not measure food or water intake, but this was not a dietary or drinking
and Procedures water study, and these endpoints are not required for this study type according to NTP.
There were no significant body weight changes that were suggestive of any palatability
issues (only increased body weights were observed).
Continued on next page ...
Page 201 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 15 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 350 mg/kg group, were instead dosed with 700
mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths
occurred as a result of the dosing error, but two male mice had convulsions and labored
breathing on the third day of overdosing. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 350 mg/kg groups,
respectively.
Metric 23:
Data Presentation and Analysis
High
General statistical methods for evaluating continuous data and incidence data were ade-
quately reported and were appropriate for those data types.
Metric 24:
Reporting of Data
Medium
Only initial and final animal body weights were reported (as means ± SE). Weekly body
weights were measured but not reported, and individual animal data were not provided.
The missing information is not expected to significantly impact the ability to interpret
the study results.
Overall Quality Determination
High
Page 202 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 16 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Renal/Kidney
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder)
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium Animals were dosed with 0, 44, 88, 175, 350, or 700 mg/kg-day, 5 days per week. Time-
adjusted doses in mg/kg-day were not reported, but can be determined using the infor-
mation provided. Dose formulations were analyzed twice during the study by gas chro-
matography and the target and measured concentrations in the solutions (mg/mL) were
reported. The concentrations generally remained with 10% of the target concentration
throughout the course of the study; however, during the second reading, the concentra-
tion used for the second-highest dose group was only 75% of the target.
Medium All mice were dosed 5 days per week for 16 weeks. Generally, the NTP guideline indi-
cates that the subchronic studies should not be more than 97 days. The longer duration
was not justified by the study authors. Dosing 5 days per week for a gavage study is
consistent with NTP guidelines.
Continued on next page ...
Page 203 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 16 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Renal/Kidney
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder)
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11:
Metric 12:
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
High
High
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9-10 weeks old), and initial body weights were re-
ported and appropriate.
Low The number of animals per cage (5/cage) was reported; however, the NTP guideline
specifies that male mice should always be housed individually. Food and water were
provided ad libiutm. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is not clear
what impact these deviations may have had on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High Organ weights and histopathological analysis were conducted on tissue(s) from this
organ/system and the outcome assessment methods are considered to be sensitive and
appropriate for this outcome of interest.
High Sufficient details of the outcome assessment protocols were provided, and outcome
assessment was carried out consistently across groups.
High Histopathology was conducted on control animals and animals from the 44, 88, 175,
350, and 700 mg/kg-day groups. The sampling size for organ weight data was reported
and was adequate.
N/A Blinding is not necessary because this outcome of interest is either not subjective in
nature, or blinding is not required (e.g., initial histopathology)
Medium The appropriateness of the negative control response for histopathology cannot be de-
termined because incidence data were not provided. The study authors did not describe
any concerns about high background levels in controls. Organ weight data for controls
appeared to be appropriate.
Domain 6: Confounding / Variable Control
Continued on next page .
Page 204 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 16 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Renal/Kidney
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder)
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 21:
Confounding Variables in Test Design
and Procedures
High
The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
There were no significant body weight changes that were suggestive of any palatability
issues (only increased body weights were observed).
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 350 mg/kg group, were instead dosed with 700
mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths
occurred as a result of the dosing error, but two male mice had convulsions and labored
breathing on the third day of overdosing. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 350 mg/kg groups,
respectively.
Metric 23:
Data Presentation and Analysis
High
General statistical methods for evaluating continuous data and incidence data were ade-
quately reported and were appropriate for those data types.
Metric 24:
Reporting of Data
Low
Organ weight data were reported quantitatively. Data were presented as means ± SE.
The text qualitatively stated that there were no gross lesions attributable to the test
chemical. Treatment-related histopathology results in the kidney were described quali-
tatively in the text. Dose groups in which lesions were observed were noted; incidences
were not specified but the text stated that lesions were observed in "all male and female
mice" at the high dose. Statistical significance was not reported.
Overall Quality Determination
High
Page 205 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 17 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cardiovascular; Immune/Hematological; Hepatic/Liver; Lung/Respiratory;
Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes,
leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes
(mandibular and mesenteric), bone marrow); Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline
phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Lung/Respiratory: Gross necropsy, histopathol-
ogy (lung, nose, trachea);
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations Medium
All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
All Outcomes: Animals were dosed with 0, 44, 88, 175, 350, or 700 mg/kg-day, 5 days
per week. Time-adjusted doses in mg/kg-day were not reported, but can be determined
using the information provided. Dose formulations were analyzed twice during the study
by gas chromatography and the target and measured concentrations in the solutions
(mg/mL) were reported. The concentrations generally remained with 10% of the target
concentration throughout the course of the study; however, during the second reading,
the concentration used for the second-highest dose group was only 75% of the target.
Continued on next page ...
Page 206 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 17 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cardiovascular; Immune/Hematological; Hepatic/Liver; Lung/Respiratory;
Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes,
leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes
(mandibular and mesenteric), bone marrow); Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline
phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Lung/Respiratory: Gross necropsy, histopathol-
ogy (lung, nose, trachea);
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10:
Exposure Frequency and Duration
Medium
All Outcomes: All mice were dosed 5 days per week for 16 weeks. Generally, the NTP
guideline indicates that the subchronic studies should not be more than 97 days. The
longer duration was not justified by the study authors. Dosing 5 days per week for a
gavage study is consistent with NTP guidelines.
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
High
All Outcomes: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values.
Metric 12:
Exposure Route and Method
High
All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
High
All Outcomes: The study used male and female B6C3F1 mice. The test animal source
(Harlan industries), age at the start of the study (9-10 weeks old), and initial body
weights were reported and appropriate.
Metric 14:
Adequacy and Consistency of Animal
Low
All Outcomes: The number of animals per cage (5/cage) was reported; however, the
Husbandry Conditions
NTP guideline specifies that male mice should always be housed individually. Food and
water were provided ad libiutm. Animal room environments (temperature, humidity,
lighting) were reported. The humidity ranged considerably from 10% to 78% . This
deviates from NTP guidelines which state humidity should not be below 35% or above
65% . It is not clear what impact these deviations may have had on the study results.
Metric 15:
Number of Animals per Group
Medium
All Outcomes: The number of animals per group (10/sex) was reported and consistent
with NTP guidelines.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Outcome Assessment Methodology
Consistency of Outcome Assessment
Sampling Adequacy
Metric 19: Blinding of Assessors
High All Outcomes: Organ weights and histopathological analysis were conducted on tis-
sue^) from this organ/system and the outcome assessment methods are considered to be
sensitive and appropriate for this outcome of interest.
High All Outcomes: Sufficient details of the outcome assessment protocols were provided,
and outcome assessment was carried out consistently across groups.
High All Outcomes: Histopathology was conducted on all control animals and animals from
the highest dose group. This is not expected to have a significant impact on the study
results because no lesions were purportedly observed for this outcome. The sampling
size for organ weight data was reported and was adequate.
N/A All Outcomes: Blinding is not necessary because this outcome of interest is either not
subjective in nature, or blinding is not required (e.g., initial histopathology)
Continued on next page ...
Page 207 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 17 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cardiovascular; Immune/Hematological; Hepatic/Liver; Lung/Respiratory;
Cardiovascular: Heart organ weights, gross necropsy, histopathology (heart); Immune/Hematological: Hematology (hematocrit, hemoglobin, erythrocytes,
leukocytes with differential, MCV, MCH, MCHC, and reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes
(mandibular and mesenteric), bone marrow); Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chemistry (serum glucose, alkaline
phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Lung/Respiratory: Gross necropsy, histopathol-
ogy (lung, nose, trachea);
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 20:
Negative Control Response
Medium
All Outcomes: The appropriateness of the negative control response for histopathology
cannot be determined because incidence data were not provided. The study authors did
not describe any concerns about high background levels in controls. Organ weight data
for controls appeared to be appropriate.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
High
All Outcomes: The study did not measure food or water intake, but this was not a di-
etary or drinking water study, and these endpoints are not required for this study type
according to NTP. There were no significant body weight changes that were suggestive
of any palatability issues (only increased body weights were observed).
Metric 22:
Health Outcomes Unrelated to
Low
All Outcomes: The study text noted that during week 4, the two highest dose groups
Exposure
were prepared incorrectly, and for the first three days of that week, the animals were ad-
ministered double the target levels. Animals in the 350 mg/kg group, were instead dosed
with 700 mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No
deaths occurred as a result of the dosing error, but two male mice had convulsions and
labored breathing on the third day of overdosing. These animals were not dosed on the
4th day of the week to allow them to recover. Dosing resumed on the 5th day. Three
males and two females died during the study due to gavage trauma. The males were
from the 175, 350, and 700 mg/kg groups, and the females were from the 175 and 350
mg/kg groups, respectively.
Metric 23:
Data Presentation and Analysis
High
All Outcomes: General statistical methods for evaluating continuous data and incidence
data were adequately reported and were appropriate for those data types.
Metric 24:
Reporting of Data
Medium
All Outcomes: Organ weight data were reported quantitatively. Data were presented as
means ± SE. The text qualitatively stated that there were no gross lesions attributable to
the test chemical. Although histopathology results were observed for one organ/system
(kidney), no statements noting the absence of effects were made for other tissues.
Overall Quality Determination
High
Page 208 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 18 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus)
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium Animals were dosed with 0, 44, 88, 175, 350, or 700 mg/kg-day, 5 days per week. Time-
adjusted doses in mg/kg-day were not reported, but can be determined using the infor-
mation provided. Dose formulations were analyzed twice during the study by gas chro-
matography and the target and measured concentrations in the solutions (mg/mL) were
reported. The concentrations generally remained with 10% of the target concentration
throughout the course of the study; however, during the second reading, the concentra-
tion used for the second-highest dose group was only 75% of the target.
Medium All mice were dosed 5 days per week for 16 weeks. Generally, the NTP guideline indi-
cates that the subchronic studies should not be more than 97 days. The longer duration
was not justified by the study authors. Dosing 5 days per week for a gavage study is
consistent with NTP guidelines.
Continued on next page ...
Page 209 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 18 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus)
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11:
Metric 12:
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
High
High
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9-10 weeks old), and initial body weights were re-
ported and appropriate.
Low The number of animals per cage (5/cage) was reported; however, the NTP guideline
specifies that male mice should always be housed individually. Food and water were
provided ad libiutm. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is not clear
what impact these deviations may have had on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High Organ weights and histopathological analysis were conducted on tissue(s) from this
organ/system and the outcome assessment methods are considered to be sensitive and
appropriate for this outcome of interest. Testis was not listed in the methods as an organ
that was being weighed, but the results reported organ weight results.
High Sufficient details of the outcome assessment protocols were provided, and outcome
assessment was carried out consistently across groups.
Low Histopathology was conducted on all control animals and animals from the highest dose
group. This is not expected to have a significant impact on the study results because no
lesions were purportedly observed for this outcome. Less than two measurements of
testis weights were available for the 88 mg/kg group. No testes weights were reported
for the 350 mg/kg group but significant changes were observed at the high dose. It is
unclear why there were deficiencies in sampling.
N/A Blinding is not necessary because this outcome of interest is either not subjective in
nature, or blinding is not required (e.g., initial histopathology)
Medium The appropriateness of the negative control response for histopathology cannot be de-
termined because incidence data were not provided. The study authors did not describe
any concerns about high background levels in controls. Organ weight data for controls
appeared to be appropriate.
Continued on next page ...
Page 210 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 18 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus)
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 6: Confounding / Variable Control
Metric 21:
Metric 22:
Confounding Variables in Test Design
and Procedures
Health Outcomes Unrelated to
Exposure
Metric 23:
Metric 24:
Data Presentation and Analysis
Reporting of Data
High The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
There were no significant body weight changes that were suggestive of any palatability
issues (only increased body weights were observed).
Low The study text noted that during week 4, the two highest dose groups were prepared
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 350 mg/kg group, were instead dosed with 700
mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths
occurred as a result of the dosing error, but two male mice had convulsions and labored
breathing on the third day of overdosing. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 350 mg/kg groups,
respectively.
High General statistical methods for evaluating continuous data and incidence data were ade-
quately reported and were appropriate for those data types.
Medium Organ weight data were reported quantitatively. Data were presented as means ± SE.
The text qualitatively stated that there were no gross lesions attributable to the test
chemical. Although histopathology results were observed for one organ/system (kid-
ney), no statements noting the absence of effects were made for other tissues.
Overall Quality Determination
High
Page 211 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 19 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/Sensory; Endocrine (Endocrine);
Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross
necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology (skeletalmuscle, bone); Ocular/Sensory: Gross necropsy, histopathology
(harderian gland); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations Medium
All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
All Outcomes: Animals were dosed with 0, 44, 88, 175, 350, or 700 mg/kg-day, 5 days
per week. Time-adjusted doses in mg/kg-day were not reported, but can be determined
using the information provided. Dose formulations were analyzed twice during the study
by gas chromatography and the target and measured concentrations in the solutions
(mg/mL) were reported. The concentrations generally remained with 10% of the target
concentration throughout the course of the study; however, during the second reading,
the concentration used for the second-highest dose group was only 75% of the target.
Continued on next page ...
Page 212 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 19 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/Sensory; Endocrine (Endocrine);
Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross
necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology (skeletalmuscle, bone); Ocular/Sensory: Gross necropsy, histopathology
(harderian gland); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10:
Exposure Frequency and Duration
Medium
All Outcomes: All mice were dosed 5 days per week for 16 weeks. Generally, the NTP
guideline indicates that the subchronic studies should not be more than 97 days. The
longer duration was not justified by the study authors. Dosing 5 days per week for a
gavage study is consistent with NTP guidelines.
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
High
All Outcomes: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values.
Metric 12:
Exposure Route and Method
High
All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
High
All Outcomes: The study used male and female B6C3F1 mice. The test animal source
(Harlan industries), age at the start of the study (9-10 weeks old), and initial body
weights were reported and appropriate.
Metric 14:
Adequacy and Consistency of Animal
Low
All Outcomes: The number of animals per cage (5/cage) was reported; however, the
Husbandry Conditions
NTP guideline specifies that male mice should always be housed individually. Food and
water were provided ad libiutm. Animal room environments (temperature, humidity,
lighting) were reported. The humidity ranged considerably from 10% to 78% . This
deviates from NTP guidelines which state humidity should not be below 35% or above
65% . It is not clear what impact these deviations may have had on the study results.
Metric 15:
Number of Animals per Group
Medium
All Outcomes: The number of animals per group (10/sex) was reported and consistent
with NTP guidelines.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Outcome Assessment Methodology
Consistency of Outcome Assessment
Sampling Adequacy
Metric 19: Blinding of Assessors
High All Outcomes: Histopathological analysis was conducted on tissue(s) from this organ/
system and histopathology is considered to be a sensitive and appropriate method for
this outcome of interest.
High All Outcomes: Sufficient details of the outcome assessment protocols were provided,
and outcome assessment was carried out consistently across groups.
Medium All Outcomes: Histopathology was conducted on all control animals and animals from
the highest dose group. This is not expected to have a significant impact on the study
results because no lesions were purportedly observed for this outcome.
N/A All Outcomes: Blinding is not necessary because this outcome of interest is either not
subjective in nature, or blinding is not required (e.g., initial histopathology)
Continued on next page ...
Page 213 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 19 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Gastrointestinal; Thyroid; Skin/Connective Tissue; Musculoskeletal; Ocular/Sensory; Endocrine (Endocrine);
Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross
necropsy, histopathology (skin); Musculoskeletal: Gross necropsy, histopathology (skeletalmuscle, bone); Ocular/Sensory: Gross necropsy, histopathology
(harderian gland); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 20:
Negative Control Response
Low
All Outcomes: The appropriateness of the negative control response for histopathology
cannot be determined because incidence data were not provided. The study authors did
not describe any concerns of high background in controls.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
High
All Outcomes: The study did not measure food or water intake, but this was not a di-
etary or drinking water study, and these endpoints are not required for this study type
according to NTP. There were no significant body weight changes that were suggestive
of any palatability issues (only increased body weights were observed).
Metric 22:
Health Outcomes Unrelated to
Low
All Outcomes: The study text noted that during week 4, the two highest dose groups
Exposure
were prepared incorrectly, and for the first three days of that week, the animals were ad-
ministered double the target levels. Animals in the 350 mg/kg group, were instead dosed
with 700 mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No
deaths occurred as a result of the dosing error, but two male mice had convulsions and
labored breathing on the third day of overdosing. These animals were not dosed on the
4th day of the week to allow them to recover. Dosing resumed on the 5th day. Three
males and two females died during the study due to gavage trauma. The males were
from the 175, 350, and 700 mg/kg groups, and the females were from the 175 and 350
mg/kg groups, respectively.
Metric 23:
Data Presentation and Analysis
High
All Outcomes: General statistical methods for evaluating continuous data and incidence
data were adequately reported and were appropriate for those data types.
Metric 24:
Reporting of Data
Medium
All Outcomes: The text qualitatively stated that there were no gross lesions attributable
to the test chemical. Although histopathology results were observed for one organ/
system (kidney), no statements noting the absence of effects were made for other tissues.
Overall Quality Determination
High
Page 214 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 20 of 28
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Chronic (>91 days) 16-weeks (mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
High Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
High All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Medium Animals were dosed with 0, 44, 88, 175, 350, or 700 mg/kg-day, 5 days per week. Time-
adjusted doses in mg/kg-day were not reported, but can be determined using the infor-
mation provided. Dose formulations were analyzed twice during the study by gas chro-
matography and the target and measured concentrations in the solutions (mg/mL) were
reported. The concentrations generally remained with 10% of the target concentration
throughout the course of the study; however, during the second reading, the concentra-
tion used for the second-highest dose group was only 75% of the target.
Medium All mice were dosed 5 days per week for 16 weeks. Generally, the NTP guideline indi-
cates that the subchronic studies should not be more than 97 days. The longer duration
was not justified by the study authors. Dosing 5 days per week for a gavage study is
consistent with NTP guidelines.
Continued on next page ...
Page 215 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 20 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Chronic (>91 days) 16-weeks (mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 11:
Metric 12:
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
High
High
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9-10 weeks old), and initial body weights were re-
ported and appropriate.
Low The number of animals per cage (5/cage) was reported; however, the NTP guideline
specifies that male mice should always be housed individually. Food and water were
provided ad libiutm. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is not clear
what impact these deviations may have had on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High Serum cholinesterase activity was determined at study termination. Absolute and rel-
ative organ weights were recorded and histopathological analysis was conducted on
tissue(s) from this organ/system. The outcome assessment methods were sensitive and
appropriate for this outcome of interest.
Medium Sufficient details of the outcome assessment protocols (organ weights and histopathol-
ogy) were provided, and outcome assessment was carried out consistently across groups.
Blood for measurement of cholinesterase activity was collected from all animals at ter-
minal sacrifice.
High Histopathology was conducted on all control animals and animals from the highest dose
group. This is not expected to have a significant impact on the study results because
no lesions were purportedly observed for this outcome. The sampling size for organ
weights and cholinesterase measurements was reported and were adequate.
N/A Blinding is not necessary because this outcome of interest is either not subjective in
nature, or blinding is not required (e.g., initial histopathology)
Medium The appropriateness of the negative control response for histopathology cannot be
determined because incidence data were not provided. The study authors did not de-
scribe any concerns about high background levels in controls. Organ weight and serum
cholinesterase data for controls appeared to be appropriate.
Continued on next page ...
Page 216 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 20 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Chronic (>91 days) 16-weeks (mice)
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Domain 6: Confounding / Variable Control
Metric 21:
Metric 22:
Confounding Variables in Test Design
and Procedures
Health Outcomes Unrelated to
Exposure
Metric 23:
Metric 24:
Data Presentation and Analysis
Reporting of Data
High The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
There were no significant body weight changes that were suggestive of any palatability
issues (only increased body weights were observed).
Low The study text noted that during week 4, the two highest dose groups were prepared
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 350 mg/kg group, were instead dosed with 700
mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths
occurred as a result of the dosing error, but two male mice had convulsions and labored
breathing on the third day of overdosing. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 350 mg/kg groups,
respectively.
High General statistical methods for evaluating continuous data and incidence data were ade-
quately reported and were appropriate for those data types.
Medium Cholinesterase activity and organ weight data were quantitatively reported as means
± SE. The text qualitatively stated that there were no gross lesions attributable to the
test chemical. Although histopathology results were observed for one organ/system
(kidney), no statements noting the absence of effects were made for other tissues.
Overall Quality Determination
High
Page 217 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 21 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations (Clinical signs)
Clinical signs (clinical observations)
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High
High
High
The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High
N/A
Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
High
High
Medium
Metric 10: Exposure Frequency and Duration
Medium
Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Animals were dosed with 0, 44, 88, 175, 350, or 700 mg/kg-day, 5 days per week. Time-
adjusted doses in mg/kg-day were not reported, but can be determined using the infor-
mation provided. Dose formulations were analyzed twice during the study by gas chro-
matography and the target and measured concentrations in the solutions (mg/mL) were
reported. The concentrations generally remained with 10% of the target concentration
throughout the course of the study; however, during the second reading, the concentra-
tion used for the second-highest dose group was only 75% of the target.
All mice were dosed 5 days per week for 16 weeks. Generally, the NTP guideline indi-
cates that the subchronic studies should not be more than 97 days. The longer duration
was not justified by the study authors. Dosing 5 days per week for a gavage study is
consistent with NTP guidelines.
Continued on next page .
Page 218 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 21 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations (Clinical signs)
Clinical signs (clinical observations)
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 11:
Metric 12:
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
High
High
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High
Low
Medium
The study used male and female B6C3F1 mice. The test animal source (Harlan indus-
tries), age at the start of the study (9-10 weeks old), and initial body weights were re-
ported and appropriate.
The number of animals per cage (5/cage) was reported; however, the NTP guideline
specifies that male mice should always be housed individually. Food and water were
provided ad libiutm. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is not clear
what impact these deviations may have had on the study results.
The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Medium
Medium
Low
Medium
Low
Animals were subjected to clinical examinations weekly in accordance with NTP guide-
lines. No methodological details were provided. The guideline also specifies that ex-
panded clinical observations should be done by a pathologist at a minimum of at least
once every other week. It is unclear if this was done.
Based on the information provided, all animals were observed daily. Additional outcome
assessment methods (e.g., the time of observations (time of day)) were not provided,
but based on the available information, there is no indication that there were differences
across groups.
All animals were observed for clinical signs, but since findings were qualitatively re-
ported, the sample size cannot be verified.
Blinding was not reported and clinical signs can be somewhat subjective in nature.
The appropriateness of the negative control response cannot be definitively determined
because incidence data were not reported, the text mentioned some clinical signs in
treated animals but did not explicitly report that there were no clinical signs in controls.
Domain 6: Confounding / Variable Control
Continued on next page .
Page 219 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 21 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations (Clinical signs)
Clinical signs (clinical observations)
Chronic (>91 days) 16-weeks (mice)
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 21:
Confounding Variables in Test Design
and Procedures
High
The study did not measure food or water intake, but this was not a dietary or drinking
water study, and these endpoints are not required for this study type according to NTP.
There were no significant body weight changes that were suggestive of any palatability
issues (only increased body weights were observed).
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 350 mg/kg group, were instead dosed with 700
mg/kg, and animals in the 700 mg/kg group were dosed with 1,400 mg/kg. No deaths
occurred as a result of the dosing error, but two male mice had convulsions and labored
breathing on the third day of overdosing. These animals were not dosed on the 4th day
of the week to allow them to recover. Dosing resumed on the 5th day. Three males and
two females died during the study due to gavage trauma. The males were from the 175,
350, and 700 mg/kg groups, and the females were from the 175 and 350 mg/kg groups,
respectively.
Metric 23:
Data Presentation and Analysis
Uninformative
Statistical methods were adequately described in general for different types of data sets;
however, methods for statistical analysis specifically for clinical observations were not
described, and the text does not report whether incidences of the observed effects were
significantly increased compared to controls. It is unclear whether the data were statisti-
cally analyzed and quantitative data were not provided to do an independent analysis.
Metric 24:
Reporting of Data
Low
Transient clinical signs were qualitatively reported in the text and statistical significance
was not specified.
Overall Quality Determination
Uninformative
Page 220 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 22 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations Medium
Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days per week. Ad-
justed daily doses were not reported, but can be determined using the information pro-
vided. Dose formulations were analyzed twice during the study by gas chromatography
and the target and measured concentrations in the solutions (mg/mL) were reported. The
concentrations generally remained with 10% of the target concentrations throughout the
course of the study; however, during the second reading, the concentration used for the
second highest dose group was only 75% of the target.
Continued on next page ...
Page 221 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 22 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10:
Exposure Frequency and Duration
Medium
Females were dosed 5 days per week for 16 weeks, and males were dosed 5 days per
week for 18 weeks. It is unclear why the duration of exposure was different for males
and females. Generally, the NTP guideline indicates that the subchronic studies should
not be more than 97 days. The 16-18-week durations were not justified by the study
authors. Dosing 5 days per week for a gavage study is consistent with NTP guidelines.
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
Medium
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Metric 12:
Exposure Route and Method
High
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
High
The study used male and female F344/N rats. The test animal source (Harlan industries),
age at the start of the study (8-9-weeks old), and initial body weights were reported and
appropriate.
Metric 14:
Adequacy and Consistency of Animal
Medium
The number of animals per cage (5/cage) was reported. Food and water were pro-
Husbandry Conditions
vided ad libitum. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is unclear
whether these deviations had an impact on the study results
Metric 15:
Number of Animals per Group
Medium
The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
The outcome assessment methods were sensitive and appropriate for the outcome of
interest. Body weights were recorded at study initiation, then weekly thereafter, and
again at termination as per NTP guidelines.
Metric 17:
Consistency of Outcome Assessment
High
Body weights were consistently assessed across groups using the same protocol.
Metric 18:
Sampling Adequacy
High
All animals were sampled for this outcome of interest.
Metric 19:
Blinding of Assessors
N/A
Blinding is not necessary because this outcome of interest is not subjective in nature, or
blinding is not required for this outcome of interest.
Metric 20:
Negative Control Response
High
The control responses were reported and were appropriate.
Domain 6: Confounding / Variable Control
Continued on next page .
Page 222 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 22 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Nutritional/Metabolic
Body weights
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 21:
Confounding Variables in Test Design
and Procedures
Medium
The initial body weights of the females in the 175 mg/kg group were statistically sig-
nificantly lower than controls by 5% . The study authors had claimed animals were nor-
malized by weight, so this is surprising. The difference didn't seem to have an impact
on later body weight measurements. The study did not measure food or water intake, but
this was not a dietary or drinking water study, and these endpoints are not required for
this study type according to NTP. There were no significant body weight changes that
were suggestive of any palatability issues (only increased body weights were observed).
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg group, were instead dosed with 350
mg/kg, and animals in the 350 mg/kg group were dosed with 700 mg/kg. As a result, 2
females in each group died, and others showed excessive signs of acute toxicity (e.g.,
ataxia, excessive salivation, gasping, and convulsions). The overdose caused no deaths
in males, and males showed no signs of toxicity. The surviving animals were not dosed
on the 4th day of the week to allow them to recover. Dosing resumed on the 5th day.
The study authors did not believe this error had a significant impact on the outcomes
assessed at the end of the study. In addition to the deaths due to overdose, three animals
died due to gavage error including 1 male and 1 female at 22 mg/kg and 1 female at 175
mg/kg.
Metric 23:
Data Presentation and Analysis
High
Statistical methods were adequately described and were appropriate for the dataset.
Statistical significance was shown where appropriate.
Metric 24:
Reporting of Data
Medium
Only initial and final animal body weights were reported (as means ± SE). Weekly body
weights were measured but were not provided, and individual animal data were not
provided. The missing information is not expected to significantly impact the ability to
interpret the study results.
Overall Quality Determination
High
Page 223 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 23 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Gastrointestinal; Musculoskeletal; Ocular/Sensory; Thyroid; Skin/Connective Tissue; Endocrine (Endocrine);
Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Ocu-
lar/Sensory: Gross necropsy, histopathology (harderian gland); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross
necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations Medium
All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
All Outcomes: Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days
per week. Adjusted daily doses were not reported, but can be determined using the in-
formation provided. Dose formulations were analyzed twice during the study by gas
chromatography and the target and measured concentrations in the solutions (mg/mL)
were reported. The concentrations generally remained with 10% of the target concen-
trations throughout the course of the study; however, during the second reading, the
concentration used for the second highest dose group was only 75% of the target.
Continued on next page ...
Page 224 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 23 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Gastrointestinal; Musculoskeletal; Ocular/Sensory; Thyroid; Skin/Connective Tissue; Endocrine (Endocrine);
Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Ocu-
lar/Sensory: Gross necropsy, histopathology (harderian gland); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross
necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10:
Exposure Frequency and Duration
Medium
All Outcomes: Females were dosed 5 days per week for 16 weeks, and males were
dosed 5 days per week for 18 weeks. It is unclear why the duration of exposure was dif-
ferent for males and females. Generally, the NTP guideline indicates that the subchronic
studies should not be more than 97 days. The 16-18-week durations were not justified
by the study authors. Dosing 5 days per week for a gavage study is consistent with NTP
guidelines.
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
Medium
All Outcomes: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values.
Metric 12:
Exposure Route and Method
High
All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High All Outcomes: The study used male and female F344/N rats. The test animal source
(Harlan industries), age at the start of the study (8-9-weeks old), and initial body weights
were reported and appropriate.
Medium All Outcomes: The number of animals per cage (5/cage) was reported. Food and water
were provided ad libitum. Animal room environments (temperature, humidity, lighting)
were reported. The humidity ranged considerably from 10% to 78% . This deviates from
NTP guidelines which state humidity should not be below 35% or above 65% . It is
unclear whether these deviations had an impact on the study results
Medium All Outcomes: The number of animals per group (10/sex) was reported and consistent
with NTP guidelines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology High All Outcomes: Flistopathological analyses were conducted on tissue(s) from this organ/
system. This method is sensitive and appropriate for this outcome of interest and is
consistent with NTP guidelines.
Metric
17:
Consistency of Outcome Assessment
High
All Outcomes: Sufficient details of the outcome assessment protocols were provided,
and outcome assessment was carried out consistently across groups.
Metric
18:
Sampling Adequacy
High
All Outcomes: Histopathology was conducted on tissues from controls and the top two
dose groups; this was appropriate given the lack of effects observed for this outcome.
Metric
19:
Blinding of Assessors
N/A
All Outcomes: Blinding is not necessary because this outcome of interest is not subjec-
tive in nature, or blinding is not required for this outcome of interest.
Continued on next page ...
Page 225 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 23 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Gastrointestinal; Musculoskeletal; Ocular/Sensory; Thyroid; Skin/Connective Tissue; Endocrine (Endocrine);
Gastrointestinal: Gross necropsy and histopathology (esophagus, gall bladder (mice only), large intestines (cecum, colon, rectum), salivary gland, small
intestines (duodenum, ileum, jejunum), stomach, mesentery, tooth); Musculoskeletal: Gross necropsy, histopathology (skeletal muscle, bone); Ocu-
lar/Sensory: Gross necropsy, histopathology (harderian gland); Thyroid: Gross necropsy and histopathology (thyroid); Skin/Connective Tissue: Gross
necropsy, histopathology (skin); Endocrine (Endocrine): Gross necropsy and histopathology (pancreas, adrenal glands, pituitary glands, parathyroid);
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 20:
Negative Control Response
Low
All Outcomes: The appropriateness of the negative control response for histopathology
cannot be determined because incidence data were not provided. The study authors did
not describe any concerns about high background in controls.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
Medium
All Outcomes: The initial body weights of the females in the 175 mg/kg group were
statistically significantly lower than controls by 5% . The study authors had claimed
animals were normalized by weight, so this is surprising. The difference didn't seem to
have an impact on later body weight measurements. The study did not measure food or
water intake, but this was not a dietary or drinking water study, and these endpoints are
not required for this study type according to NTP. There were no significant body weight
changes that were suggestive of any palatability issues (only increased body weights
were observed).
Metric 22:
Health Outcomes Unrelated to
Low
All Outcomes: The study text noted that during week 4, the two highest dose groups
Exposure
were prepared incorrectly, and for the first three days of that week, the animals were
administered double the target levels. Animals in the 175 mg/kg group, were instead
dosed with 350 mg/kg, and animals in the 350 mg/kg group were dosed with 700 mg/kg.
As a result, 2 females in each group died, and others showed excessive signs of acute
toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The overdose
caused no deaths in males, and males showed no signs of toxicity. The surviving animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed
on the 5th day. The study authors did not believe this error had a significant impact on
the outcomes assessed at the end of the study. In addition to the deaths due to overdose,
three animals died due to gavage error including 1 male and 1 female at 22 mg/kg and 1
female at 175 mg/kg.
Metric 23:
Data Presentation and Analysis
High
All Outcomes: Statistical methods were adequately described and were appropriate for
the dataset. Statistical significance was shown where appropriate.
Metric 24:
Reporting of Data
High
All Outcomes: Negative gross and histopathological findings were qualitatively reported
in the text. The text indicated that histopathological examinations resulted in no signifi-
cantly increased incidences of lesions that could be attributed to treatment (except for in
the brain).
Overall Quality Determination
High
Page 226 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 24 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Cardiovascular: Heart organ weights, gross necropsy histopathology (heart); Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chem-
istry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney:
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/Respiratory; Gross necropsy, histopathology
(lung, nose, trachea); Immune/Hematological; Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1; Test Substance Identity
Metric 2; Test Substance Source
Metric 3; Test Substance Purity
High All Outcomes: The test substance was identified definitively as tris(2-chloroethyl phos-
phate) CASRN 115-96-8. A structure was also provided.
High All Outcomes: The test substance was manufactured by Stauffer Chemical Company
and obtained from the analytical chemistry laboratory, Midwest Research Institute. The
lot number was provided.
High All Outcomes: The test chemical purity was 98% , and was both provided by the sup-
plier and confirmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2; Test Design
Metric 4; Negative and Vehicle Controls High
Metric 5; Positive Controls N/A
Metric 6; Randomized Allocation of Animals Medium
All Outcomes: The study included concurrent negative vehicle (corn oil) controls and
conditions were consistent with the animals that were treated.
All Outcomes: Positive controls are not required for this study type.
All Outcomes: Animals were distributed into weight classes, and assigned to cages
using a random number table. Cages were then assigned to treatment and control groups
using another random number table.
Domain 3; Exposure Characterization
Metric 7;
Metric 8;
Metric 9;
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations Medium
All Outcomes: Stability studies were conducted. The bulk chemical was stable for
at least 2 weeks in sealed containers at room temperature. Stability was monitored
throughout the study and no degradation was observed. Additionally, the test solutions
(TCEP in corn oil) were also stable for 21 days in the dark at room temperature or open
to air and light for 3 hours. For the studies, the dose formulations were stored at 0-5
degrees C for 2 weeks. Fresh solutions were made every two weeks
All Outcomes: All animals were gavaged on the same schedule. Gavage volumes were
reported and were consistent across groups.
All Outcomes: Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days
per week. Adjusted daily doses were not reported, but can be determined using the in-
formation provided. Dose formulations were analyzed twice during the study by gas
chromatography and the target and measured concentrations in the solutions (mg/mL)
were reported. The concentrations generally remained with 10% of the target concen-
trations throughout the course of the study; however, during the second reading, the
concentration used for the second highest dose group was only 75% of the target.
Continued on next page ...
Page 227 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 24 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Cardiovascular: Heart organ weights, gross necropsy histopathology (heart); Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chem-
istry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney:
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/Respiratory; Gross necropsy, histopathology
(lung, nose, trachea); Immune/Hematological; Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10;
Exposure Frequency and Duration
Medium
All Outcomes: Females were dosed 5 days per week for 16 weeks, and males were
dosed 5 days per week for 18 weeks. It is unclear why the duration of exposure was dif-
ferent for males and females. Generally, the NTP guideline indicates that the subchronic
studies should not be more than 97 days. The 16-18-week durations were not justified
by the study authors. Dosing 5 days per week for a gavage study is consistent with NTP
guidelines.
Metric 11:
Number of Exposure Groups and
Dose/Concentration Spacing
Medium
All Outcomes: The study tested 5 dose groups plus a control. This is consistent with
NTP guidelines. The spacing was sufficient to identify NOAEL and LOAEL values.
Metric 12;
Exposure Route and Method
High
All Outcomes: Animals were exposed via gavage. The study provided detailed methods
and the route is appropriate for the test substance.
Domain 4; Test Animals
Metric 13; Test Animal Characteristics
Metric 14; Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15; Number of Animals per Group
High All Outcomes: The study used male and female F344/N rats. The test animal source
(Harlan industries), age at the start of the study (8-9-weeks old), and initial body weights
were reported and appropriate.
Medium All Outcomes: The number of animals per cage (5/cage) was reported. Food and water
were provided ad libitum. Animal room environments (temperature, humidity, lighting)
were reported. The humidity ranged considerably from 10% to 78% . This deviates from
NTP guidelines which state humidity should not be below 35% or above 65% . It is
unclear whether these deviations had an impact on the study results.
Medium All Outcomes: The number of animals per group (10/sex) was reported and consistent
with NTP guidelines.
Domain 5; Outcome Assessment
Metric 16;
Outcome Assessment Methodology
Metric 17; Consistency of Outcome Assessment
Metric 18; Sampling Adequacy
Metric 19; Blinding of Assessors
High All Outcomes: Organ weights and histopathological examinations were conducted on
tissue(s) from this organ/system. The methods of outcome assessment were sensitive
and appropriate for the outcomes of interest.
High All Outcomes: Sufficient details of the outcome assessment protocols (organ weights
and histopathology) were provided, and outcome assessment was carried out consis-
tently across groups.
High All Outcomes: Organ weights were measured from all surviving animals. Histopathol-
ogy was conducted on tissues from controls and the top two dose groups; this was ap-
propriate given the lack of effects observed for this outcome.
N/A All Outcomes: Blinding is not necessary because this outcome of interest is not subjec-
tive in nature, or is not required (initial histopathology).
Continued on next page ...
Page 228 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 24 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Cardiovascular: Heart organ weights, gross necropsy histopathology (heart); Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chem-
istry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney:
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/Respiratory; Gross necropsy, histopathology
(lung, nose, trachea); Immune/Hematological; Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 20;
Negative Control Response
Medium
All Outcomes: The appropriateness of the negative control response for histopathology
cannot be determined because incidence data were not provided. The study authors did
not describe any concerns about high background in controls. Organ weight data for
controls appeared to be appropriate.
Domain 6; Confounding / Variable Control
Metric 21;
Confounding Variables in Test Design
and Procedures
Medium
All Outcomes: The initial body weights of the females in the 175 mg/kg group were
statistically significantly lower than controls by 5% . The study authors had claimed
animals were normalized by weight, so this is surprising. The difference didn't seem to
have an impact on later body weight measurements. The study did not measure food or
water intake, but this was not a dietary or drinking water study, and these endpoints are
not required for this study type according to NTP. There were no significant body weight
changes that were suggestive of any palatability issues (only increased body weights
were observed).
Metric 22;
Health Outcomes Unrelated to
Low
All Outcomes: The study text noted that during week 4, the two highest dose groups
Exposure
were prepared incorrectly, and for the first three days of that week, the animals were
administered double the target levels. Animals in the 175 mg/kg group, were instead
dosed with 350 mg/kg, and animals in the 350 mg/kg group were dosed with 700 mg/kg.
As a result, 2 females in each group died, and others showed excessive signs of acute
toxicity (e.g., ataxia, excessive salivation, gasping, and convulsions). The overdose
caused no deaths in males, and males showed no signs of toxicity. The surviving animals
were not dosed on the 4th day of the week to allow them to recover. Dosing resumed
on the 5th day. The study authors did not believe this error had a significant impact on
the outcomes assessed at the end of the study. In addition to the deaths due to overdose,
three animals died due to gavage error including 1 male and 1 female at 22 mg/kg and 1
female at 175 mg/kg.
Metric 23;
Data Presentation and Analysis
High
All Outcomes: Statistical methods were adequately described and were appropriate for
the dataset. Statistical significance was shown where appropriate.
Metric 24;
Reporting of Data
High
All Outcomes: Organ weight data were reported quantitatively. Data were presented as
means ± SE. Negative gross and histopathological findings were qualitatively reported
in the text. The text indicated that histopathological examinations resulted in no signifi-
cantly increased incidences of lesions that could be attributed to treatment (except for in
the brain).
Continued on next page ...
Page 229 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 24 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Cardiovascular; Hepatic/Liver; Renal/Kidney; Lung/Respiratory; Immune/Hematological;
Cardiovascular: Heart organ weights, gross necropsy histopathology (heart); Hepatic/Liver: Liver weights, gross necropsy, histopathology, clinical chem-
istry (serum glucose, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, sorbitol dehydrogenase, cholesterol); Renal/Kidney:
Serum chemistry (BUN, creatinine), organ weights, gross necropsy, histopathology (kidney, bladder); Lung/Respiratory; Gross necropsy, histopathology
(lung, nose, trachea); Immune/Hematological; Hematology (hematocrit, hemoglobin, erythrocytes, leukocytes with differential, MCV, MCH, MCHC, and
reticulocyte count), thymus weights, gross pathology, histopathology (spleen, thymus, lymph nodes (mandibular and mesenteric), bone marrow);
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain Metric
Rating
Comments
Overall Quality Determination
High
Page 230 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 25 of 28
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations Medium
Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days per week. Ad-
justed daily doses were not reported, but can be determined using the information pro-
vided. Dose formulations were analyzed twice during the study by gas chromatography
and the target and measured concentrations in the solutions (mg/mL) were reported. The
concentrations generally remained with 10% of the target concentrations throughout the
course of the study; however, during the second reading, the concentration used for the
second highest dose group was only 75% of the target.
Continued on next page ...
Page 231 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 25 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 10:
Metric 11:
Metric 12:
Exposure Frequency and Duration
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
Medium
Medium
High
Females were dosed 5 days per week for 16 weeks, and males were dosed 5 days per
week for 18 weeks. It is unclear why the duration of exposure was different for males
and females. Generally, the NTP guideline indicates that the subchronic studies should
not be more than 97 days. The 16-18-week durations were not justified by the study
authors. Dosing 5 days per week for a gavage study is consistent with NTP guidelines.
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female F344/N rats. The test animal source (Harlan industries),
age at the start of the study (8-9-weeks old), and initial body weights were reported and
appropriate.
Medium The number of animals per cage (5/cage) was reported. Food and water were pro-
vided ad libitum. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is unclear
whether these deviations had an impact on the study results
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
High Serum Cholinesterase activity was determined at study termination. Absolute and rel-
ative organ weights were measured, and all animals were subjected to gross necropsy.
Brain tissue was examined histologically and included a second more detailed patholog-
ical review. The outcome assessment methodologies were sensitive to the outcome of
interest.
High Sufficient details of the outcome assessment protocols (organ weights and histopathol-
ogy) were provided, and outcome assessment was carried out consistently across groups.
Blood for measurement of cholinesterase activity was collected from all surviving ani-
mals at terminal sacrifice.
High The sampling size for organ weight data was reported and was adequate. Histopathology
was conducted on all control animals and animals from the two highest dose groups;
brain tissues were also examined from the 88 mg/kg group.
High Initial histopathology was not blinded, a second re-examination of the hippocampus was
evaluated in a blinded manner by a pathologist.
Continued on next page ...
Page 232 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 25 of 28
... continued from previous page
Study Citation: NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Health Neurological/Behavioral
Outcome(s):
Reported Health Serum cholinesterase activity (special study 16-day and 16-week studies, and as part of serum chemistry in 2-yr study), brain weights, gross necropsy,
Effect(s): histopathology (brain)
Duration: Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 5469669
Domain
Metric
Rating
Comments
Metric 20: Negative Control Response
High Control responses (including the absence of brain lesions) were reported and appropri-
ate.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22:
Health Outcomes Unrelated to
Exposure
Metric 23:
Metric 24:
Data Presentation and Analysis
Reporting of Data
Medium The initial body weights of the females in the 175 mg/kg group were statistically sig-
nificantly lower than controls by 5% . The study authors had claimed animals were nor-
malized by weight, so this is surprising. The difference didn't seem to have an impact
on later body weight measurements. The study did not measure food or water intake, but
this was not a dietary or drinking water study, and these endpoints are not required for
this study type according to NTP. There were no significant body weight changes that
were suggestive of any palatability issues (only increased body weights were observed).
Low The study text noted that during week 4, the two highest dose groups were prepared
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg group, were instead dosed with 350
mg/kg, and animals in the 350 mg/kg group were dosed with 700 mg/kg. As a result, 2
females in each group died, and others showed excessive signs of acute toxicity (e.g.,
ataxia, excessive salivation, gasping, and convulsions). The overdose caused no deaths
in males, and males showed no signs of toxicity. The surviving animals were not dosed
on the 4th day of the week to allow them to recover. Dosing resumed on the 5th day.
The study authors did not believe this error had a significant impact on the outcomes
assessed at the end of the study. In addition to the deaths due to overdose, three animals
died due to gavage error including 1 male and 1 female at 22 mg/kg and 1 female at 175
mg/kg.
High Statistical methods were adequately described and were appropriate for the dataset.
Statistical significance was shown where appropriate.
Medium Cholinesterase activity and organ weights were quantitatively reported as means ± SE,
and the number of animals sampled was reported. Histopathology results were described
in the text. Incidences were reported for some, but not all dose groups and statistical
significance was noted.
Overall Quality Determination
High
Page 233 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 26 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus)
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations Medium
Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days per week. Ad-
justed daily doses were not reported, but can be determined using the information pro-
vided. Dose formulations were analyzed twice during the study by gas chromatography
and the target and measured concentrations in the solutions (mg/mL) were reported. The
concentrations generally remained with 10% of the target concentrations throughout the
course of the study; however, during the second reading, the concentration used for the
second highest dose group was only 75% of the target.
Continued on next page ...
Page 234 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 26 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus)
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10:
Metric 11:
Metric 12:
Exposure Frequency and Duration
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
Medium
Medium
High
Females were dosed 5 days per week for 16 weeks, and males were dosed 5 days per
week for 18 weeks. It is unclear why the duration of exposure was different for males
and females. Generally, the NTP guideline indicates that the subchronic studies should
not be more than 97 days. The 16-18-week durations were not justified by the study
authors. Dosing 5 days per week for a gavage study is consistent with NTP guidelines.
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female F344/N rats. The test animal source (Harlan industries),
age at the start of the study (8-9-weeks old), and initial body weights were reported and
appropriate.
Medium The number of animals per cage (5/cage) was reported. Food and water were pro-
vided ad libitum. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is unclear
whether these deviations had an impact on the study results
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Outcome Assessment Methodology
Consistency of Outcome Assessment
Sampling Adequacy
Metric 19: Blinding of Assessors
High Organ weights and Histopathological analysis were conducted on tissue(s) from this
organ/system. These methods are sensitive and appropriate for this outcome of interest
and are consistent with NTP guidelines.
High Sufficient details of the outcome assessment protocols were provided, and outcome
assessment was carried out consistently across groups.
Low Only two samples for testis weights in males from the 44 mg/kg group were collected,
and a mean was not determined. It is unclear why only two samples were collected. No
testis weights were reported at the high dose. Histopathology was conducted on tissues
from controls and the top two dose-groups; this was appropriate given the lack of effects
observed for this outcome.
N/A Blinding is not necessary because this outcome of interest is not subjective in nature, or
blinding is not required for this outcome of interest.
Continued on next page ...
Page 235 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 26 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Reproductive/Developmental
Gross necropsy and histopathology (clitoral gland, epididymis, mammary glands, ovary, preputial gland, prostate, seminal vesicle, testis, uterus)
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 20:
Negative Control Response
Medium
The appropriateness of the negative control response for histopathology cannot be deter-
mined because incidence data were not provided. The study authors did not describe any
concerns of high background in controls. Organ weight data for controls appeared to be
appropriate.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
Medium
The initial body weights of the females in the 175 mg/kg group were statistically sig-
nificantly lower than controls by 5% . The study authors had claimed animals were nor-
malized by weight, so this is surprising. The difference didn't seem to have an impact
on later body weight measurements. The study did not measure food or water intake, but
this was not a dietary or drinking water study, and these endpoints are not required for
this study type according to NTP. There were no significant body weight changes that
were suggestive of any palatability issues (only increased body weights were observed).
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg group, were instead dosed with 350
mg/kg, and animals in the 350 mg/kg group were dosed with 700 mg/kg. As a result, 2
females in each group died, and others showed excessive signs of acute toxicity (e.g.,
ataxia, excessive salivation, gasping, and convulsions). The overdose caused no deaths
in males, and males showed no signs of toxicity. The surviving animals were not dosed
on the 4th day of the week to allow them to recover. Dosing resumed on the 5th day.
The study authors did not believe this error had a significant impact on the outcomes
assessed at the end of the study. In addition to the deaths due to overdose, three animals
died due to gavage error including 1 male and 1 female at 22 mg/kg and 1 female at 175
mg/kg.
Metric 23:
Data Presentation and Analysis
High
Statistical methods were adequately described and were appropriate for the dataset.
Statistical significance was shown where appropriate.
Metric 24:
Reporting of Data
Medium
Negative gross and histopathological findings were qualitatively reported in the text. The
text indicated that histopathological examinations resulted in no significantly increased
incidences of lesions that could be attributed to treatment (except for in the brain). Testis
weights were reported as means ± SE, but weights for some groups were not reported
and this was not explained by the study authors.
Overall Quality Determination
High
Page 236 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 27 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
High The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
High The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Preparation and Storage of Test High
Substance
Consistency of Exposure High
Administration
Reporting of Doses/Concentrations Medium
Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days per week. Ad-
justed daily doses were not reported, but can be determined using the information pro-
vided. Dose formulations were analyzed twice during the study by gas chromatography
and the target and measured concentrations in the solutions (mg/mL) were reported. The
concentrations generally remained with 10% of the target concentrations throughout the
course of the study; however, during the second reading, the concentration used for the
second highest dose group was only 75% of the target.
Continued on next page ...
Page 237 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 27 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10:
Metric 11:
Metric 12:
Exposure Frequency and Duration
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
Medium
Medium
High
Females were dosed 5 days per week for 16 weeks, and males were dosed 5 days per
week for 18 weeks. It is unclear why the duration of exposure was different for males
and females. Generally, the NTP guideline indicates that the subchronic studies should
not be more than 97 days. The 16-18-week durations were not justified by the study
authors. Dosing 5 days per week for a gavage study is consistent with NTP guidelines.
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female F344/N rats. The test animal source (Harlan industries),
age at the start of the study (8-9-weeks old), and initial body weights were reported and
appropriate.
Medium The number of animals per cage (5/cage) was reported. Food and water were pro-
vided ad libitum. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is unclear
whether these deviations had an impact on the study results
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Metric 19:
Outcome Assessment Methodology
Consistency of Outcome Assessment
Sampling Adequacy
Blinding of Assessors
Metric 20: Negative Control Response
High Animals were observed twice daily for morbidity and mortality. The outcome assess-
ment was sensitive and appropriate for the outcome of interest.
Medium There was consistency in the timing and methods of outcome assessment within each
sex; however, since males and females were exposed for different durations, the tim-
ing of the outcome assessments is different between sexes, making it difficult to make
comparisons across sex.
High All animals were sampled for this outcome of interest.
N/A Blinding is not necessary because this outcome of interest is not subjective in nature, or
blinding is not required for this outcome of interest.
High No control animals died.
Domain 6: Confounding / Variable Control
Continued on next page ...
Page 238 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 27 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Mortality
Survival
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 21:
Confounding Variables in Test Design
and Procedures
Medium
The initial body weights of the females in the 175 mg/kg group were statistically sig-
nificantly lower than controls by 5% . The study authors had claimed animals were nor-
malized by weight, so this is surprising. The difference didn't seem to have an impact
on later body weight measurements. The study did not measure food or water intake, but
this was not a dietary or drinking water study, and these endpoints are not required for
this study type according to NTP. There were no significant body weight changes that
were suggestive of any palatability issues (only increased body weights were observed).
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg group, were instead dosed with 350
mg/kg, and animals in the 350 mg/kg group were dosed with 700 mg/kg. As a result, 2
females in each group died, and others showed excessive signs of acute toxicity (e.g.,
ataxia, excessive salivation, gasping, and convulsions). The overdose caused no deaths
in males, and males showed no signs of toxicity. The surviving animals were not dosed
on the 4th day of the week to allow them to recover. Dosing resumed on the 5th day.
The study authors did not believe this error had a significant impact on the outcomes
assessed at the end of the study. In addition to the deaths due to overdose, three animals
died due to gavage error including 1 male and 1 female at 22 mg/kg and 1 female at 175
mg/kg.
Metric 23:
Data Presentation and Analysis
High
Statistical methods were adequately described and were appropriate for the dataset.
Statistical significance was shown where appropriate.
Metric 24:
Reporting of Data
Medium
Survival data were quantitatively reported and described in the text Some animals died
as a result of an accidental overdose during the 4th week, and other animals died due to
gavage trauma. The causes of death for some animals weren't specified other than being
"treatment-related." The times of death are specified.
Overall Quality Determination
High
Page 239 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 28 of 28
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations (Clinical observations)
Clinical signs (clinical observations)
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High
High
High
The test substance was identified definitively as tris(2-chloroethyl phosphate) CASRN
115-96-8. A structure was also provided.
The test substance was manufactured by Stauffer Chemical Company and obtained from
the analytical chemistry laboratory, Midwest Research Institute. The lot number was
provided.
The test chemical purity was 98% , and was both provided by the supplier and con-
firmed via analysis (NMR and elemental analysis) by the study laboratory.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High
N/A
Medium
The study included concurrent negative vehicle (corn oil) controls and conditions were
consistent with the animals that were treated.
Positive controls are not required for this study type.
Animals were distributed into weight classes, and assigned to cages using a random
number table. Cages were then assigned to treatment and control groups using another
random number table.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
High
High
Medium
Stability studies were conducted. The bulk chemical was stable for at least 2 weeks in
sealed containers at room temperature. Stability was monitored throughout the study
and no degradation was observed. Additionally, the test solutions (TCEP in corn oil)
were also stable for 21 days in the dark at room temperature or open to air and light for
3 hours. For the studies, the dose formulations were stored at 0-5 degrees C for 2 weeks.
Fresh solutions were made every two weeks
All animals were gavaged on the same schedule. Gavage volumes were reported and
were consistent across groups.
Animals were dosed with 0, 22, 44, 88, 175, or 350 mg/kg-day, 5 days per week. Ad-
justed daily doses were not reported, but can be determined using the information pro-
vided. Dose formulations were analyzed twice during the study by gas chromatography
and the target and measured concentrations in the solutions (mg/mL) were reported. The
concentrations generally remained with 10% of the target concentrations throughout the
course of the study; however, during the second reading, the concentration used for the
second highest dose group was only 75% of the target.
Continued on next page .
Page 240 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 28 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations (Clinical observations)
Clinical signs (clinical observations)
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 10:
Metric 11:
Metric 12:
Exposure Frequency and Duration
Number of Exposure Groups and
Dose/Concentration Spacing
Exposure Route and Method
Medium
Medium
High
Females were dosed 5 days per week for 16 weeks, and males were dosed 5 days per
week for 18 weeks. It is unclear why the duration of exposure was different for males
and females. Generally, the NTP guideline indicates that the subchronic studies should
not be more than 97 days. The 16-18-week durations were not justified by the study
authors. Dosing 5 days per week for a gavage study is consistent with NTP guidelines.
The study tested 5 dose groups plus a control. This is consistent with NTP guidelines.
The spacing was sufficient to identify NOAEL and LOAEL values.
Animals were exposed via gavage. The study provided detailed methods and the route is
appropriate for the test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
High The study used male and female F344/N rats. The test animal source (Harlan industries),
age at the start of the study (8-9-weeks old), and initial body weights were reported and
appropriate.
Medium The number of animals per cage (5/cage) was reported. Food and water were pro-
vided ad libitum. Animal room environments (temperature, humidity, lighting) were
reported. The humidity ranged considerably from 10% to 78% . This deviates from NTP
guidelines which state humidity should not be below 35% or above 65% . It is unclear
whether these deviations had an impact on the study results.
Medium The number of animals per group (10/sex) was reported and consistent with NTP guide-
lines.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Medium
Medium
Medium
Medium
Animals were subjected to clinical examinations weekly in accordance with NTP guide-
lines. No additional methodological details were provided. The guideline also specifies
that expanded clinical observations should be done by a pathologist at a minimum of at
least once every other week. It is unclear if this was done.
Based on the information provided, all animals were observed daily. Additional outcome
assessment methods (e.g., the time of observations (time of day)) were not provided,
but based on the available information, there is no indication that there were differences
across groups.
All animals were observed for clinical signs, but since negative findings were qualita-
tively reported, the sample size cannot be verified.
Blinding was not reported and clinical signs can be somewhat subjective in nature; how-
ever, lack of blinding is not expected to have a significant impact on results.
Continued on next page .
Page 241 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469669 Table: 28 of 28
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). NTP Toxicology and Carcinogenesis Studies of Tris(2-chloroethyl) Phosphate (CAS No. 115-96-8) in F344/N Rats and B6C3F1 Mice
(Gavage Studies). National Toxicology Program Technical Report Series 3911-233.
Unspecified clinical observations (Clinical observations)
Clinical signs (clinical observations)
Chronic (>91 days) 16-weeks (females) 18-weeks (males) - rat
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469669
Domain
Metric
Rating
Comments
Metric 20:
Negative Control Response
Low
The appropriateness of the negative control response cannot be definitively determined
because incidence data were not reported, the text mentioned some clinical signs in
treated animals but did not explicitly report that there were no clinical signs in controls.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
Medium
The initial body weights of the females in the 175 mg/kg group were statistically sig-
nificantly lower than controls by 5% . The study authors had claimed animals were nor-
malized by weight, so this is surprising. The difference didn't seem to have an impact
on later body weight measurements. The study did not measure food or water intake, but
this was not a dietary or drinking water study, and these endpoints are not required for
this study type according to NTP. There were no significant body weight changes that
were suggestive of any palatability issues (only increased body weights were observed).
Metric 22:
Health Outcomes Unrelated to
Low
The study text noted that during week 4, the two highest dose groups were prepared
Exposure
incorrectly, and for the first three days of that week, the animals were administered
double the target levels. Animals in the 175 mg/kg group, were instead dosed with 350
mg/kg, and animals in the 350 mg/kg group were dosed with 700 mg/kg. As a result, 2
females in each group died, and others showed excessive signs of acute toxicity (e.g.,
ataxia, excessive salivation, gasping, and convulsions). The overdose caused no deaths
in males, and males showed no signs of toxicity. The surviving animals were not dosed
on the 4th day of the week to allow them to recover. Dosing resumed on the 5th day.
The study authors did not believe this error had a significant impact on the outcomes
assessed at the end of the study. In addition to the deaths due to overdose, three animals
died due to gavage error including 1 male and 1 female at 22 mg/kg and 1 female at 175
mg/kg.
Metric 23:
Data Presentation and Analysis
Uninformative
Statistical methods were adequately described in general for different types of data sets;
however, methods for statistical analysis specifically for clinical observations were not
described, and the text does not report whether incidences of the observed effects were
significantly increased compared to controls. It is unclear whether the data were statisti-
cally analyzed and quantitative data were not provided to do an independent analysis.
Metric 24:
Reporting of Data
Low
Data for exposure-related findings were described in the text. Results were only men-
tioned for some dose groups.
Overall Quality Determination
Uninformative
Page 242 of 275
-------
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Tris(2-chloroethyl) phosphate (TCEP) Human Health Hazard Animal Toxicology Evaluation HERO ID: 5469568 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sala, M., Gu, Z. G„ Moens, G„ Chouroulinkov, I. (1982). In vivo and in vitro biological effects of the flame retardants tris(2,3-dibromopropyl) phosphate
and tris(2-chlorethyl)orthophosphate. European lournal of Cancer & Clinical Oncology 18(12): 1337-1344.
Cancer/Carcinogenesis (Lung); Skin/Connective Tissue (Skin tumors);
Cancer/Carcinogenesis (Lung): Due to the lack of concurrent control data and the reporting of the laboratory historical data, it is difficult to interpret the
significance of the reported lung cancer effects (i.e., study authors report that TCEP induced lung adenomas when used as a promoter).; Skin/Connective
Tissue (Skin tumors): Short term skin test: mouse skin treated with TCEP showed that sebaceous glands were not suppressed and hyperplasia was not
induced. Long term skin test: mouse skin treated with TCEP showed negative results for complete carcinogenic or promoting activity on mouse skin.;
Chronic (>91 days) Long term skin test
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469568
Domain Metric Rating Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity High All Outcomes: The substance was characterized by nomenclature and commercial name
(i.e., Tris(2-chloroethyl), orthophosphate; Genomoll P). The density (chemical property)
was also reported.
Metric 2: Test Substance Source High All Outcomes: source: Hoechst
Metric 3: Test Substance Purity Low All Outcomes: Purity and/or grade of test substance were not reported.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls
Positive Controls
Randomized Allocation of Animals
Uninformative All Outcomes: Concurrent solvent controls were not included.
N/A All Outcomes: The study type does not require a positive control.
Medium All Outcomes: Female mice were randomized into groups.
Domain 3: Exposure Characterization
Metric
7:
Preparation and Storage of Test
Substance
Low
All Outcomes: Information on preparation and storage was not reported and lack of
details could substantially impact results (e.g. storage for long-term studies).
Metric
8:
Consistency of Exposure
Administration
High
All Outcomes: Details of exposure administration were reported and exposures were
administered consistently across study groups.
Metric
9:
Reporting of Doses/Concentrations
High
All Outcomes: Administered doses were reported without ambiguity.
Metric
10:
Exposure Frequency and Duration
High
All Outcomes: The exposure frequency and duration of exposure were reported and
appropriate for this study type and/or outcome(s) of interest.
Metric
11:
Number of Exposure Groups and
Dose/Concentration Spacing
High
All Outcomes: Despite no justification the selected range sufficiently covered the full
range of responses.
Metric
12:
Exposure Route and Method
High
All Outcomes: The route and method of exposure were reported and were suited to the
test substance.
Domain 4: Test Animals
Metric 13: Test Animal Characteristics
High All Outcomes: The test animal species, strain, sex, age, and starting body weight were
reported, and the test animal was obtained from a commercial source or laboratory-
maintained colony. The test species and strain were an appropriate animal model for the
evaluation of the specific outcome(s) of interest (e.g., routinely used for similar study
types).
Continued on next page ...
Page 243 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 5469568 Table: 1 of 1
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Sala, M., Gu, Z. G„ Moens, G„ Chouroulinkov, I. (1982). In vivo and in vitro biological effects of the flame retardants tris(2,3-dibromopropyl) phosphate
and tris(2-chlorethyl)orthophosphate. European lournal of Cancer & Clinical Oncology 18(12): 1337-1344.
Cancer/Carcinogenesis (Lung); Skin/Connective Tissue (Skin tumors);
Cancer/Carcinogenesis (Lung): Due to the lack of concurrent control data and the reporting of the laboratory historical data, it is difficult to interpret the
significance of the reported lung cancer effects (i.e., study authors report that TCEP induced lung adenomas when used as a promoter).; Skin/Connective
Tissue (Skin tumors): Short term skin test: mouse skin treated with TCEP showed that sebaceous glands were not suppressed and hyperplasia was not
induced. Long term skin test: mouse skin treated with TCEP showed negative results for complete carcinogenic or promoting activity on mouse skin.;
Chronic (>91 days) Long term skin test
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
5469568
Domain
Metric
Rating
Comments
Metric 14: Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Low
Low
All Outcomes: Husbandry conditions were not sufficiently reported to evaluate if hus-
bandry was adequate and whether differences occurred between control and exposed
populations. These deficiencies are likely to have a substantial impact on results.
All Outcomes: The reported number of animals per study group was lower than the
typical number used in studies of the same or similar type, but sufficient for statistical
analysis.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
High All Outcomes: The outcome assessment methodology addressed the intended out-
come^) of interest and the assessment methodology was sensitive and appropriate for
the outcomes(s) of interest.
High All Outcomes: Outcomes were assessed consistently across study groups (e.g., at the
same time after initial exposure) using the same protocol in all study groups.
High All Outcomes: Reported information indicates the study used adequate sampling for the
outcome(s) of interest.
N/A Cancer/Carcinogenesis (Lung): Outcomes are not subjective and blinding of assessors is
not necessary.; Skin/Connective Tissue (Skin tumors): Study outcomes are not subjec-
tive and blinding of assessors is not necessary.
Uninformative All Outcomes: There were no concurrent negative controls.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Low
High
Low
High
All Outcomes: Body weight changes, food/water intake and differences in use of
surgery were not reported
All Outcomes: Based on reported information, there were no health outcomes unrelated
to exposure.
All Outcomes: Statistical analysis was performed but not described adequately.
All Outcomes: Data for exposure-related findings were presented for all outcomes by
exposure group.
Overall Quality Determination
Uninformative
Page 244 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 790471 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Hazleton Laboratories, (1983). Screening of priority chemicals for potential reproductive hazard (final report) with attachments and cover sheet.
Reproductive/Developmental
Live/dead pups, litter size, litter weight, pup weight change, nongravid uteri staining
Reproductive/Developmental 8 day Reproductive Study - Reproductive
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
790471
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1:
Test Substance Identity
High
Test substances used were identified by established nomenclature.
Metric 2:
Test Substance Source
High
Test Substance was supplied by NIOSH.
Metric 3:
Test Substance Purity
High
Each chemical purity was determined by Hazelton laboratory.
Domain 2: Test Design
Metric 4:
Negative and Vehicle Controls
High
Vehicle control with corn oil were used for the test substance.
Metric 5:
Positive Controls
N/A
Positive Controls for this study were not necessary.
Metric 6:
Randomized Allocation of Animals
Low
No mention of allocation of animals in this study.
Domain 3: Exposure Characterization
Metric 7:
Preparation and Storage of Test
High
Preparation of test substances for experiment was adequate for study.
Substance
Metric 8:
Consistency of Exposure
High
Exposure administration was consistent.
Administration
Metric 9:
Reporting of Doses/Concentrations
High
All doses were reported.
Metric 10:
Exposure Frequency and Duration
Low
There was no premating dosing and gestational dosing was on GD 7- 14.
Metric 11:
Number of Exposure Groups and
N/A
There is only one exposure dose in the reproductive study.
Dose/Concentration Spacing
Metric 12:
Exposure Route and Method
High
Exposure route and method was suitable for this study.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
High
Test animal characteristics were explained in detail.
Metric 14:
Adequacy and Consistency of Animal
High
Animal husbandry conditions were reported.
Husbandry Conditions
Metric 15:
Number of Animals per Group
Medium
50 pregnant mice were dosed at 940 mg/kg-d.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
The assessment of outcome methodology was suitable for this study.
Metric 17:
Consistency of Outcome Assessment
High
Consistency of outcome assessment was suitable for this study.
Metric 18:
Sampling Adequacy
High
Sampling in this study was adequate.
Metric 19:
Blinding of Assessors
N/A
Assessors did not need to be blind for this study.
Metric 20:
Negative Control Response
High
Negative control/vehicle response was appropriately compared to the treated animals.
Continued on next page ...
Page 245 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 790471 Table: 1 of 1
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
Hazleton Laboratories, (1983). Screening of priority chemicals for potential reproductive hazard (final report) with attachments and cover sheet.
Reproductive/Developmental
Live/dead pups, litter size, litter weight, pup weight change, nongravid uteri staining
Reproductive/Developmental 8 day Reproductive Study - Reproductive
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
790471
Metric Rating Comments
Domain
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Overall Quality Determination
High No reported differences in the variables between each animal.
High No outcomes related to health exposure.
High Statistical analysis was suitable for this study.
High All data was reported in this study.
High
Page 246 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 1 of 5
Study Citation: Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Health Reproductive/Developmental; Reproductive/Developmental;
Outcome(s):
Reported Health Reproductive/Developmental: Resorptions (nonpregnant dams); viability, litter size, and litter weight, male:female ratio; in F1 and F2 offspring: body
Effect(s): weight/body weight gain; Reproductive/Developmental; Resorptions (nonpregnant dams); viability, litter size, and litter weight, male:female ratio; in F1
and F2 offspring: body weight/body weight gain;
Duration: Reproductive/Developmental From gestation day 10 and through weaning
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 3008543
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was definitively identified as TCEP. The CASRN was
provided.
High All Outcomes: The test substance source was specified (Sigma-Aldrich).
Medium All Outcomes: The purity of the test substance was 97% . The identity of any impurities
was not reported.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls High
Metric 5: Positive Controls N/A
Metric 6: Randomized Allocation of Animals Low
All Outcomes: The study specified that corn oil was the vehicle control.
All Outcomes: Not required by study type.
All Outcomes: The study stated that dam weights on gestation day (GD) 9 were strati-
fied and dose groups assigned so that the average weight for each dose group was com-
parable. Pups were not directly dosed; however, it was not indicated how they were
allocated to specific (behavioral) testing schedules. The method of culling offspring was
not stated.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium All Outcomes: Minimal information about test substance preparation and storage con-
ditions were reported. The study stated that TCEP was dissolved in corn oil and made
fresh every 3-4 days.
High All Outcomes: Dosing was described; it appeared that doses were administered consis-
tently across study groups. The gavage volume was 0.5 mL/kg.
High All Outcomes: The doses administered were reported without ambiguity. The study
noted that the highest dose tested for TCEP started out as 125 mg/kg-day; however,
owing to toxicity, the highest dose was reduced to 90 mg/kg-day after 5 days of dosing.
High All Outcomes: The dosing period was appropriate to assess developmental toxicity;
dosing of dams occurred from GD 10 through weaning (encompassing the period of pup
growth/development).
High All Outcomes: Three dose groups plus the control were used. The dose groups were
justified by the study authors; they were based on a pilot study in non-pregnant females
to determine doses that did not produce overt toxicity. The highest dose used at the start
of the study was lowered owing to overt toxicity. The highest dose used thereafter was
high enough to induce some toxicity in dams (e.g., increased liver weight).
High All Outcomes: The route and method were suited to the test substance.
Continued on next page ...
Page 247 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 1 of 5
Domain
... continued from previous page
Study Citation: Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Health Reproductive/Developmental; Reproductive/Developmental;
Outcome(s):
Reported Health Reproductive/Developmental: Resorptions (nonpregnant dams); viability, litter size, and litter weight, male:female ratio; in F1 and F2 offspring: body
Effect(s): weight/body weight gain; Reproductive/Developmental; Resorptions (nonpregnant dams); viability, litter size, and litter weight, male:female ratio; in F1
and F2 offspring: body weight/body weight gain;
Duration: Reproductive/Developmental From gestation day 10 and through weaning
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 3008543
Metric
Rating
Comments
Domain 4: Test Animals
Metric 13: Test Animal Characteristics Medium
Metric 14: Adequacy and Consistency of Animal High
Husbandry Conditions
Metric 15: Number of Animals per Group Low
All Outcomes: The study indicated that Long-Evans rats were obtained from a commer-
cial source (Charles River Laboratories) on GD 2. Although ages were not stated, the
dams' pregnancy status identified them as mature. Starting body weights were shown
graphically (Figure 1).
All Outcomes: Husbandry conditions, including temperature, humidity, light-dark cycle,
and diet and water availability were reported in adequate detail.
All Outcomes: The number of dams per group ("n" was presumably 14 based on the
indication that 56 animals were used in the study and there were 3 dose groups plus con-
trols) is below the number typically recommended for prenatal developmental toxicity
studies (typically about 20).
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology High All Outcomes: The endpoints evaluated the outcomes of interest (the study was es-
pecially interested in evaluating thyrotoxicity and developmental neurotoxicity). In-
formation on endpoints evaluated in the offspring are described: Developmental pa-
rameters and growth - Two dams that did not deliver were evaluated for resorptions;
litter endpoints evaluated included litter size and litter weight on postnatal day (PND)2,
male:female ratio of pups, pup viability, and pup body weights pre- and post-weaning.
Liver - absolute and relative organ weights. Thyrotoxicity - serum T3 and T4; Devel-
opmental neurotoxicity - brain weight, serum and brain acetylcholinesterase (AchE)
activity in the serum and brain, neurobehavior (righting relflex in pre-weaning pups,
standard locomotor activity in pre- and post-weaning pups and adult offspring, loco-
motor activity including a lighting change, elevated zero maze, and modified functional
observational battery (FOB) in post-weaning pups and adult offspring, and Morris maze
in adult offspring.
Metric 17: Consistency of Outcome Assessment High All Outcomes: The timing of outcome assessments appeared to be consistent across
groups. For developmental neurobehavior, a table (Table 1) was included indicating
testing sequence/timing of testing for the various types of tests. Organ weight data for
offspring (body, brain, and liver weights) were shown for the same time points (e.g.,
PND6, PND22). With respect to offspring body weights, the study authors noted that,
post-weaning, pups were allocated to different testing timelines; data were interpolated
to common weigh days and combined within litter.
Continued on next page ...
Page 248 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 1 of 5
... continued from previous page
Study Citation: Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Health Reproductive/Developmental; Reproductive/Developmental;
Outcome(s):
Reported Health Reproductive/Developmental: Resorptions (nonpregnant dams); viability, litter size, and litter weight, male:female ratio; in F1 and F2 offspring: body
Effect(s): weight/body weight gain; Reproductive/Developmental; Resorptions (nonpregnant dams); viability, litter size, and litter weight, male:female ratio; in F1
and F2 offspring: body weight/body weight gain;
Duration: Reproductive/Developmental From gestation day 10 and through weaning
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 3008543
Domain
Metric
Rating
Comments
Metric 18:
Sampling Adequacy
Medium
All Outcomes: Endpoints in offspring were evaluated in all the animals allocated to
specific groups. Litter parameters (e.g., litter size and litter weight) were evaluated in
all pups on PND2, righting reflex was measured in all pups prior to culling (PNDs 2-
4), organ weights were recorded in all animals scheduled for sacrifice (e.g., all culled
pups on PND6, the 10/sex/group pups sacrificed at weaning and as adults). Behavioral
tests were typically conducted using 1 male and 1 female from each litter (the "n" was
relatively low because fewer than the recommended number of dams/group was used to
start the study).
Metric 19:
Blinding of Assessors
Medium
All Outcomes: Blinding is not required for many outcomes (organ weights, serum and
brain measurements of AchE activity, offspring body weights). Neurobehavioral tests
typically require blinding. The study indicated that for the FOB and elevated zero maze,
the observer was unaware of treatment group (i.e., blinded) and testing over the days
was counterbalanced across dose groups and sex. For the Morris water maze, swimming
was monitored by video and digitized for computer analysis. There was no mention of
blinding for righting reflex or motor activity measurements (however, the manner in
which these endpoints were measured were likely less subjective).
Metric 20:
Negative Control Response
Medium
All Outcomes: Developmental parameters and growth - data for litter size, litter weight,
male:female ratio of pups, and pup viability were not provided; offspring body weights
in controls were shown graphically in Figure 2. Liver - Liver weights were shown for all
groups including controls in Table 2. Thyroid - Thyroid hormone levels were shown for
all groups including controls in Supplemental Figure 1. Developmental neurotoxicity -
Brain weights for all groups including controls were shown in Table 2; brain AchE data
(but not serum AchE data) for controls was provided in the text. For behavioral tests,
data were typically shown for controls for any effects in which there was a potential
treatment-related effects; results for controls were not included for all tests that reported
negative results.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
Medium
All Outcomes: Not all information to determine confounding was provided; however,
reported information did not identify differences.
Metric 22:
Health Outcomes Unrelated to
Exposure
Medium
All Outcomes: Information neither supported nor dismissed the suggestion that were
differences among dose groups with respect to outcomes unrelated to exposure.
Metric 23:
Data Presentation and Analysis
High
All Outcomes: Statistical analyses were described in adequate detail. The litter was the
unit for statistical analyses.
Continued on next
page...
Page 249 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 1 of 5
... continued from previous page
Study Citation: Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Health Reproductive/Developmental; Reproductive/Developmental;
Outcome(s):
Reported Health Reproductive/Developmental: Resorptions (nonpregnant dams); viability, litter size, and litter weight, male:female ratio; in F1 and F2 offspring: body
Effect(s): weight/body weight gain; Reproductive/Developmental; Resorptions (nonpregnant dams); viability, litter size, and litter weight, male:female ratio; in F1
and F2 offspring: body weight/body weight gain;
Duration: Reproductive/Developmental From gestation day 10 and through weaning
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 3008543
Domain
Metric
Rating
Comments
Metric 24: Reporting of Data
Medium All Outcomes: In general, negative results were reported qualitatively in the text; other
results (including any result that was potentially treatment-related) were reported by
exposure group and sex (when applicable). Developmental parameters and growth -
negative results (litter size and weight, male:female ratio, viability) were reported qual-
itatively; offspring body weights were presented graphically in Figure 2; Liver - Liver
weights (PNDs 6 and 22) were provided in Table 2; Thyroid - T3 and T4 levels were
provided in Supplemental Table 1; Developmental neurotoxicity - Brain weight data
were reported in Table 2; brain and serum AchE activity reported in the text; for neu-
robehavioral tests, negative results were qualitatively; endpoints within tests that exam-
ined potential effects were provided in more quantitative formats (e.g., latency to leave
closed arm in elevated zero maze test, hindlimb strength).
Overall Quality Determination
High
Page 250 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 2 of 5
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Nutritional/Metabolic
Maternal body weights
Reproductive/Developmental From gestation day 10 and through weaning
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
3008543
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was definitively identified as TCEP. The CASRN was provided.
High The test substance source was specified (Sigma-Aldrich).
Medium The purity of the test substance was 97% . The identity of any impurities was not re-
ported.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High The study specified that corn oil was the vehicle control.
N/A Not required by study type.
Medium The study stated that dam weights on gestation day (GD) 9 were stratified and dose
groups assigned so that the average weight for each dose group was comparable.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Minimal information about test substance preparation and storage conditions were re-
ported. The study stated that TCEP was dissolved in corn oil and made fresh every 3-4
days.
High Dosing was described; it appeared that doses were administered consistently across
study groups. The gavage volume was 0.5 mL/kg.
High The doses administered were reported without ambiguity. The study noted that the high-
est dose tested for TCEP started out as 125 mg/kg-day; however, owing to toxicity, the
highest dose was reduced to 90 mg/kg-day after 5 days of dosing.
High The dosing period was appropriate to assess developmental toxicity; dosing of dams
occurred from GD 10 through weaning (encompassing the period of pup growth/
development).
High Three dose groups plus the control were used. The dose groups were justified by the
study authors; they were based on a pilot study in non-pregnant females to determine
doses that did not produce overt toxicity. The highest dose used at the start of the study
was lowered owing to overt toxicity. The highest dose used thereafter was high enough
to induce toxicity in dams (e.g., increased liver weight).
High The route and method were suited to the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Medium The study indicated that Long-Evans rats were obtained from a commercial source
(Charles River Laboratories) on GD 2. Although ages were not stated, the dams' preg-
nancy status identified them as mature. Starting body weights were shown graphically
(Figure 1).
Continued on next page ...
Page 251 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 2 of 5
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
... continued from previous page
Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Nutritional/Metabolic
Maternal body weights
Reproductive/Developmental From gestation day 10 and through weaning
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
3008543
Domain
Metric
Rating
Comments
Metric 14: Adequacy and Consistency of Animal High
Husbandry Conditions
Metric 15: Number of Animals per Group Low
Husbandry conditions, including temperature, humidity, light-dark cycle, and diet and
water availability were reported in adequate detail.
The number of females per group ("n" was presumably 14 based on the indication that
56 animals were used in the study and there were 3 dose groups plus controls) is below
the number typically recommended for prenatal developmental toxicity studies (n - 20).
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric
OO
Metric
19:
Metric
20:
Outcome Assessment Methodology High
Consistency of Outcome Assessment High
Sampling Adequacy Medium
Blinding of Assessors N/A
Negative Control Response Medium
The study indicated that dams were weighed twice weekly and more frequently around
birth.
Based on the data (presented graphically in Figure 1), it appears that body weights were
assessed consistently across group (i.e., measured at the same time points for all dose
groups, including controls).
Although not stated, body weights were presumably assessed in all dams.
Blinding is not required for this outcome.
Body weight data for controls were presented graphically in Figure 1.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Medium Not all information to determine confounding was provided; however, reported informa-
tion did not identify differences.
Medium Information neither supported nor dismissed the suggestion that were differences among
dose groups with respect to outcomes unrelated to exposure.
N/A Statistical analyses were not necessary/not required (negative results across groups; a
10% change from controls could be used as a benchmark for a biologically significant
effect).
Medium The study presented body weight data for dams graphically (Figure 1), In the text, the
study authors indicated that there were no differences in body weight throughout dosing.
Overall Quality Determination
High
Page 252 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 3 of 5
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Thyroid
Serum T3 and T4 in dams; F1 offspring: thyroid endpoints (T3 and T4 levels)
Reproductive/Developmental From gestation day 10 and through weaning
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
3008543
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was definitively identified as TCEP. The CASRN was provided.
High The test substance source was specified (Sigma-Aldrich).
Medium The purity of the test substance was 97% . The identity of any impurities was not re-
ported.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High The study specified that corn oil was the vehicle control.
N/A Not required by study type.
Medium The study stated that dam weights on gestation day (GD) 9 were stratified and dose
groups assigned so that the average weight for each dose group was comparable.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Minimal information about test substance preparation and storage conditions were re-
ported. The study stated that TCEP was dissolved in corn oil and made fresh every 3-4
days.
High Dosing was described; it appeared that doses were administered consistently across
study groups. The gavage volume was 0.5 mL/kg.
High The doses administered were reported without ambiguity. The study noted that the high-
est dose tested for TCEP started out as 125 mg/kg-day; however, owing to toxicity, the
highest dose was reduced to 90 mg/kg-day after 5 days of dosing.
High The dosing period was appropriate to assess developmental toxicity; dosing of dams
occurred from GD 10 through weaning (encompassing the period of pup growth/
development).
High Three dose groups plus the control were used. The dose groups were justified by the
study authors; they were based on a pilot study in non-pregnant females to determine
doses that did not produce overt toxicity. The highest dose used at the start of the study
was lowered owing to overt toxicity. The highest dose used thereafter was high enough
to induce toxicity in dams (e.g., increased liver weight).
High The route and method were suited to the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Medium The study indicated that Long-Evans rats were obtained from a commercial source
(Charles River Laboratories) on GD 2. Although ages were not stated, the dams' preg-
nancy status identified them as mature. Starting body weights were shown graphically
(Figure 1).
Continued on next page ...
Page 253 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 3 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Thyroid
Serum T3 and T4 in dams; F1 offspring: thyroid endpoints (T3 and T4 levels)
Reproductive/Developmental From gestation day 10 and through weaning
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
3008543
Domain
Metric
Rating
Comments
Metric 14:
Adequacy and Consistency of Animal
High
Husbandry conditions, including temperature, humidity, light-dark cycle, and diet and
Husbandry Conditions
water availability were reported in adequate detail.
Metric 15:
Number of Animals per Group
Low
The number of females per group ("n" was presumably 14 based on the indication that
56 animals were used in the study and there were 3 dose groups plus controls) is below
the number typically recommended for prenatal developmental toxicity studies (n - 20).
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Medium
The study evaluated serum T3 and T4; thyroid weights and thyroid histology were not
assessed.
Metric 17:
Consistency of Outcome Assessment
High
Serum T3 and T4 levels were measured in dams from all groups sacrificed on postnatal
day (PND) 23.
Metric 18:
Sampling Adequacy
Medium
Although not explicitly stated, the study language suggest liver weights were assessed in
all dams.
Metric 19:
Blinding of Assessors
N/A
Blinding is not required for this outcome.
Metric 20:
Negative Control Response
High
Thyroid hormone data for controls were provided (Supplemental Table 1). The study
also noted that control values for this study were similar to control values for another
study that was conducted in tandem.
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
Medium
Not all information to determine confounding was provided; however, reported informa-
and Procedures
tion did not identify differences.
Metric 22:
Health Outcomes Unrelated to
Medium
Information neither supported nor dismissed the suggestion that were differences among
Exposure
dose groups with respect to outcomes unrelated to exposure.
Metric 23:
Data Presentation and Analysis
High
Statistical analyses were described in adequate detail.
Metric 24:
Reporting of Data
High
Serum thyroid hormone data were reported by dose group (Supplemental Table 1). The
study authors indicated that TCEP treatment did not alter T3 or T4 levels in dams.
Overall Quality Determination
High
Page 254 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 4 of 5
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Hepatic/Liver
Liver weights in dams; F1 offspring: liver weight
Reproductive/Developmental From gestation day 10 and through weaning
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
3008543
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was definitively identified as TCEP. The CASRN was provided.
High The test substance source was specified (Sigma-Aldrich).
Medium The purity of the test substance was 97% . The identity of any impurities was not re-
ported.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High The study specified that corn oil was the vehicle control.
N/A Not required by study type.
Medium The study stated that dam weights on gestation day (GD) 9 were stratified and dose
groups assigned so that the average weight for each dose group was comparable.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium Minimal information about test substance preparation and storage conditions were re-
ported. The study stated that TCEP was dissolved in corn oil and made fresh every 3-4
days.
High Dosing was described; it appeared that doses were administered consistently across
study groups. The gavage volume was 0.5 mL/kg.
High The doses administered were reported without ambiguity. The study noted that the high-
est dose tested for TCEP started out as 125 mg/kg-day; however, owing to toxicity, the
highest dose was reduced to 90 mg/kg-day after 5 days of dosing.
High The dosing period was appropriate to assess developmental toxicity; dosing of dams
occurred from GD 10 through weaning (encompassing the period of pup growth/
development).
High Three dose groups plus the control were used. The dose groups were justified by the
study authors; they were based on a pilot study in non-pregnant females to determine
doses that did not produce overt toxicity. The highest dose used at the start of the study
was lowered owing to overt toxicity. The highest dose used thereafter was high enough
to induce toxicity in dams (e.g., increased liver weight).
High The route and method were suited to the test substance.
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Medium The study indicated that Long-Evans rats were obtained from a commercial source
(Charles River Laboratories) on GD 2. Although ages were not stated, the dams' preg-
nancy status identified them as mature. Starting body weights were shown graphically
(Figure 1).
Continued on next page ...
Page 255 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 4 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Hepatic/Liver
Liver weights in dams; F1 offspring: liver weight
Reproductive/Developmental From gestation day 10 and through weaning
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
3008543
Domain
Metric
Rating
Comments
Metric 14:
Metric 15:
Adequacy and Consistency of Animal
Husbandry Conditions
Number of Animals per Group
High
Low
Husbandry conditions, including temperature, humidity, light-dark cycle, and diet and
water availability were reported in adequate detail.
The number of females per group ("n" was presumably 14 based on the indication that
56 animals were used in the study and there were 3 dose groups plus controls) is below
the number typically recommended for prenatal developmental toxicity studies (n - 20).
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Metric 19:
Metric 20:
Outcome Assessment Methodology
Consistency of Outcome Assessment
Sampling Adequacy
Blinding of Assessors
Negative Control Response
Medium
High
Medium
N/A
High
The study evaluated liver weights; no other liver endpoints (clinical chemistry changes
indicative of liver toxicity, liver histology) were assessed.
Liver weights were measured in dams from all dose groups after sacrifice on postnatal
day (PND) 23.
Although not stated, body weights were presumably assessed in all dams.
Blinding is not required for this outcome.
Liver weight data for controls were provided (Table 2).
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design
and Procedures
Metric 22: Health Outcomes Unrelated to
Exposure
Metric 23: Data Presentation and Analysis
Metric 24: Reporting of Data
Medium
Medium
High
Medium
Not all information to determine confounding was provided; however, reported informa-
tion did not identify differences.
Information neither supported nor dismissed the suggestion that were differences among
dose groups with respect to outcomes unrelated to exposure.
Statistical analyses were described in adequate detail.
Absolute and relative liver weight data were reported by dose group (Table 2). The study
authors indicated that absolute and relative liver were increased by treatment; absolute
liver weight was not statistically significantly increased and relative liver weight was
significantly increased at the highest dose (p = 0.0249).
Overall Quality Determination
High
Page 256 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 5 of 5
Study Citation: Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Health Mortality; Neurological/Behavioral;
Outcome(s):
Reported Health Mortality: Mortality in dams; Neurological/Behavioral: Serum AchE in dams; F1 offspring: righting reflex, motor activity, modified FOB, anxiety
Effect(s): behaviors, cognitive learning, AchE activity, brain weight;
Duration: Reproductive/Developmental From gestation day 10 and through weaning
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 3008543
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was definitively identified as TCEP. The CASRN was
provided.
High All Outcomes: The test substance source was specified (Sigma-Aldrich).
Medium All Outcomes: The purity of the test substance was 97% . The identity of any impurities
was not reported.
Domain 2: Test Design
Metric 4
Metric 5
Metric 6
Negative and Vehicle Controls High
Positive Controls N/A
Randomized Allocation of Animals Medium
All Outcomes: The study specified that corn oil was the vehicle control.
All Outcomes: Not required by study type.
All Outcomes: The study stated that dam weights on gestation day (GD) 9 were strati-
fied and dose groups assigned so that the average weight for each dose group was com-
parable.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8: Consistency of Exposure
Administration
Metric 9: Reporting of Doses/Concentrations
Metric 10: Exposure Frequency and Duration
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
Medium All Outcomes: Minimal information about test substance preparation and storage con-
ditions were reported. The study stated that TCEP was dissolved in corn oil and made
fresh every 3-4 days.
High All Outcomes: Dosing was described; it appeared that doses were administered consis-
tently across study groups. The gavage volume was 0.5 mL/kg.
High All Outcomes: The doses administered were reported without ambiguity. The study
noted that the highest dose tested for TCEP started out as 125 mg/kg-day; however,
owing to toxicity, the highest dose was reduced to 90 mg/kg-day after 5 days of dosing.
High All Outcomes: The dosing period was appropriate to assess developmental toxicity;
dosing of dams occurred from GD 10 through weaning (encompassing the period of pup
growth/development).
High All Outcomes: Three dose groups plus the control were used. The dose groups were
justified by the study authors; they were based on a pilot study in non-pregnant females
to determine doses that did not produce overt toxicity. The highest dose used at the start
of the study was lowered owing to overt toxicity. The highest dose used thereafter was
high enough to induce toxicity in dams (e.g., increased liver weight).
High All Outcomes: The route and method were suited to the test substance.
Domain 4: Test Animals
Continued on next page .
Page 257 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 5 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Mortality; Neurological/Behavioral;
Mortality: Mortality in dams; Neurological/Behavioral: Serum AchE in dams; F1 offspring:
behaviors, cognitive learning, AchE activity, brain weight;
Reproductive/Developmental From gestation day 10 and through weaning
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
3008543
righting reflex, motor activity, modified FOB, anxiety
Domain
Metric
Rating
Comments
Metric 13:
Test Animal Characteristics
Medium
All Outcomes: The study indicated that Long-Evans rats were obtained from a commer-
cial source (Charles River Laboratories) on GD 2. Although ages were not stated, the
dams' pregnancy status identified them as mature. Starting body weights were shown
graphically (Figure 1).
Metric 14:
Adequacy and Consistency of Animal
Husbandry Conditions
High
All Outcomes: Husbandry conditions, including temperature, humidity, light-dark cycle,
and diet and water availability were reported in adequate detail.
Metric 15:
Number of Animals per Group
Low
All Outcomes: The number of females per group ("n" was presumably 14 based on the
indication that 56 animals were used in the study and there were 3 dose groups plus con-
trols) is below the number typically recommended for prenatal developmental toxicity
studies (n - 20).
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment Medium
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Medium Mortality: The outcome (mortality) was presumably evaluated via active monitoring of
the animals.; Neurological/Behavioral: The study evaluated clinical signs of toxicity and
serum acetylcholinesterase (AchE) activity; no other neurological endpoints (e.g., brain
histology) were assessed.
Mortality: The timing of assessments of mortality was not explicitly specified (presum-
ably animals were observed at the time of dosing).; Neurological/Behavioral: Serum
AChE activity was measured in dams from all dose groups after sacrifice on postnatal
day (PND) 23. Clinical signs were presumably assessed consistently across groups.
Medium All Outcomes: Although not explicitly stated, the study language suggest liver weights
were assessed in all dams.
N/A All Outcomes: Blinding is not required for this outcome.
Medium Mortality: It was not explicitly stated that no mortality occurred in controls; however,
the study reported that there was evidence of toxicity at the highest dose of TCEP and
once the highest dose was lowered, no toxicity was observed thereafter (presumably in
any dose group).; Neurological/Behavioral: Based on the information provided in the
study report, controls likely showed no toxic signs of toxicity. Serum AChE activity in
controls was reported in the text.
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium
and Procedures
Metric 22: Health Outcomes Unrelated to Medium
Exposure
All Outcomes: Not all information to determine confounding was provided; however,
reported information did not identify differences.
All Outcomes: Information neither supported nor dismissed the suggestion that were
differences among dose groups with respect to outcomes unrelated to exposure.
Continued on next page ...
Page 258 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 3008543 Table: 5 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
Moser, V. C., Phillips, P. M„ Hedge, J, M„ McDaniel, K, L, (2015), Neurotoxicological and thyroid evaluations of rats developmentally exposed to
tris( l,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloro-2-ethyl)phosphate (TCEP), Neurotoxicology and Teratology 52(Pt B):236-247,
Mortality; Neurological/Behavioral;
Mortality: Mortality in dams; Neurological/Behavioral: Serum AchE in dams; F1 offspring:
behaviors, cognitive learning, AchE activity, brain weight;
Reproductive/Developmental From gestation day 10 and through weaning
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
3008543
righting reflex, motor activity, modified FOB, anxiety
Domain
Metric
Rating
Comments
Metric 23:
Data Presentation and Analysis
High
Mortality: Statistical analyses were not reported. Findings were considered negative
across groups; the sacrifice of 2/14 animals at the highest dose compared to a presumed
incidence of 0/14 in controls is not statistically significant (based on Fisher's test per-
formed for this review).; Neurological/Behavioral: Statistical analyses were described in
adequate detail.
Metric 24:
Reporting of Data
Medium
Mortality: The study indicated that two dams in the highest dose group at the start of the
study (125 mg/kg-day) were sacrificed moribund after about 3 days of dosing; mortal-
ity in this group was presumably 2/14 compared to 0/14 for controls (but this was not
explicitly specified).; Neurological/Behavioral: The study reported neurological signs
of toxicity (tremors) in two rats treated at the highest dose of TCEP initially tested (125
mg/kg-day for the first 5 days) and indicated that there was no toxicity observed after the
dose was reduced (presumably in any group). With respect to AChE activity, quantita-
tive data were not provided; however, it was indicated in the text that AChE levels in all
dose groups were within 97% -104% of control values.
Overall Quality Determination
High
Page 259 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 1 of 5
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Mortality
Mortality
Reproductive/Developmental About 35 weeks
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
10603716
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively: nomenclature: tris(2-
chloroethyl)phosphate and CASRN: 115-96-8. The compound was also identified as
TCEP by gas chromatography.
High The source of the test substance was a manufacturer (Aldrich); a batch/lot number was
indicated (HT0090787).
High TCEP was comprehensively analyzed to determine the purity of the test chemical, which
was indicated to be >98% pure. Observed effects were likely due to the test substance
itself.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High An appropriate control group was used throughout the study (i.e., control mice were
administered the corn oil vehicle only).
N/A Positive controls were not required by study type.
Low The study did not indicate how animals were allocated to study groups. It was men-
tioned that animals were randomly paired for some phases of the experiment.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8:
Metric 9:
Metric 10:
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
Exposure Frequency and Duration
High
Medium
High
High
The test substance was mixed in corn oil; each dose level was independently formulated.
Aliquots of each formulation (including the control) were sent for analysis at various
time points during the study. The stock concentration was 8 mg/mL. Formulation anal-
yses showed that TCEP mixed at this concentration was stable for 3 weeks at room
temperature; dose formulations were prepared at least every three weeks.
Appendix I notes that the time of gavage dosing varied up to 1 hr among doses (one
exception occurred). Other details of exposure administration are incompletely reported
(e.g., gavage volume). Any missing information is unlikely to have a substantial impact
on results (especially since a published protocol that complied to GLP standards was
used).
Doses in mg/kg-day were reported without ambiguity.
The study frequency/duration was adequate to detect effects pertaining to the outcome of
interest.
Continued on next page ...
Page 260 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 1 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Mortality
Mortality
Reproductive/Developmental About 35 weeks
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
10603716
Domain
Metric
Rating
Comments
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High The dose range-finding (Task 1) and continuous breeding (Task 3) phases of the study
utilized at least 3 dose levels and a concurrent control; the dose intervals were typically
two-fold. The offspring assessment (Task 4) included two dose levels plus the control
owing to there being too few offspring to analyze at the high-dose. Doses were ini-
tially selected (based on the dose range-finding study) to induce some systemic toxicity
without severe toxicity/death at the high-dose (and to allow for the identification of a
NOAEL).
High The study used a route of exposure (oral) that was considered appropriate (i.e., applica-
ble to humans). Analyses of dosing formulations confirmed that the method of exposure
was suited to the test substance (i.e., the test substance was stably mixed with corn oil
for administration via gavage).
Domain 4: Test Animals
Metric 13:
Metric 14:
Test Animal Characteristics
Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium Based on OECD guidelines, the rat is the preferred species for most assessments of
reproductive toxicity (e.g., based on guidelines for one- and two-generation toxicity
tests, combined repeated-dose with reproductive/developmental toxicity); a rationale
should have been provided for the use of mice in this study. The species and strain (VAF
Crl: Swiss CD-I [ICR]BR outbred albino mice), sex (both), age (e.g., 8 weeks at the
start of Task 1 and 11 weeks at the start of Task 2), and starting body weights of the
animals on the study were reported. Mice were purchased from a commercial source
(Charles River Breeding Laboratories, Inc.).
High The following husbandry conditions were reported: temperature, light-dark cycle (14
hours light/10 hours dark), and food and water availability and were similar for treated
groups of mice and controls. Humidity was not reported.
Medium The number of animals per group was in line with the numbers usually used for studies
of this type. Reproduction studies typically aim to achieve about 20 successful pregnan-
cies per dose group; for some tasks in this study, there were 20 pairs/treatment group,
which resulted in fewer than 20 pregnancies per group (e.g., fertility was 18-19 out of 20
during Task 2). The number of animals per group was adequate to evaluate the outcome
of interest.
Domain 5: Outcome Assessment
Metric 16:
Metric 17:
Metric 18:
Metric 19:
Outcome Assessment Methodology High
Consistency of Outcome Assessment High
Sampling Adequacy High
Blinding of Assessors N/A
The outcome analysis (monitoring of mortality, presumably daily but not explicitly
specified) was an appropriate method to evaluate the outcome of interest.
Outcomes were assessed consistently across study groups.
Mortality was evaluated in all animals.
Blinding is not applicable to this outcome (which is not subjective).
Continued on next page ...
Page 261 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 1 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Mortality
Mortality
Reproductive/Developmental About 35 weeks
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
10603716
Domain
Metric
Rating
Comments
Metric 20:
Negative Control Response
High
The biological response of the negative control group was adequate (little to no mortality
occurred in controls depending on the phase of the study).
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
Medium
The study did not report all information to determine confounding, but the information
and Procedures
reported did not identify differences. In general, the body weights of treated animals
were similar to controls throughout the study.
Metric 22:
Health Outcomes Unrelated to
High
Details on outcomes unrelated to exposure were reported. The study indicated that,
Exposure
during quarantine, representative animals were sacrificed and evaluated for antibodies
against mouse viruses and parasites. The health status of sentinel animals maintained in
the same room as treated animals were monitored as well (tested for viral antibodies).
Animals tested negative for infections throughout the study.
Metric 23:
Data Presentation and Analysis
High
Appropriate statistical analyses were performed (or could be performed) for all end-
points.
Metric 24:
Reporting of Data
High
The number of animals that died was reported by phase of the study and by group.
Overall Quality Determination
High
Page 262 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 2 of 5
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Nutritional/Metabolic
Body weight and water consumption
Reproductive/Developmental About 35 weeks
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
10603716
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively: nomenclature: tris(2-
chloroethyl)phosphate and CASRN: 115-96-8. The compound was also identified as
TCEP by gas chromatography.
High The source of the test substance was a manufacturer (Aldrich); a batch/lot number was
indicated (HT0090787).
High TCEP was comprehensively analyzed to determine the purity of the test chemical, which
was indicated to be >98% pure. Observed effects were likely due to the test substance
itself.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High An appropriate control group was used throughout the study (i.e., control mice were
administered the corn oil vehicle only).
N/A Positive controls were not required by study type.
Low The study did not indicate how animals were allocated to study groups. It was men-
tioned that animals were randomly paired for some phases of the experiment.
Domain 3: Exposure Characterization
Metric 7:
Metric 8:
Metric 9:
Metric 10:
Metric 11:
Preparation and Storage of Test
Substance
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
Exposure Frequency and Duration
Number of Exposure Groups and
Dose/Concentration Spacing
High
Medium
High
High
High
The test substance was mixed in corn oil; each dose level was independently formulated.
Aliquots of each formulation (including the control) were sent for analysis at various
time points during the study. The stock concentration was 8 mg/mL. Formulation anal-
yses showed that TCEP mixed at this concentration was stable for 3 weeks at room
temperature; dose formulations were prepared at least every three weeks.
Appendix I notes that the time of gavage dosing varied up to 1 hr among doses (one
exception occurred). Other details of exposure administration are incompletely reported
(e.g., gavage volume). Any missing information is unlikely to have a substantial impact
on results (especially since a published protocol that complied to GLP standards was
used).
Doses in mg/kg-day were reported without ambiguity.
The study frequency/duration was adequate to detect effects pertaining to the outcome of
interest.
The dose range-finding (Task 1) and continuous breeding (Task 3) phases of the study
utilized at least 3 dose levels and a concurrent control; the dose intervals were typically
two-fold. The offspring assessment (Task 4) included two dose levels plus the control
owing to there being too few offspring to analyze at the high-dose. Doses were ini-
tially selected (based on the dose range-finding study) to induce some systemic toxicity
without severe toxicity/death at the high-dose (and to allow for the identification of a
NOAEL).
Continued on next page ...
Page 263 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 2 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Nutritional/Metabolic
Body weight and water consumption
Reproductive/Developmental About 35 weeks
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
10603716
Domain
Metric
Rating
Comments
Metric 12:
Exposure Route and Method
High
The study used a route of exposure (oral) that was considered appropriate (i.e., applica-
ble to humans). Analyses of dosing formulations confirmed that the method of exposure
was suited to the test substance (i.e., the test substance was stably mixed with corn oil
for administration via gavage).
Domain 4:
Test Animals
Metric 13:
Test Animal Characteristics
Medium
Based on OECD guidelines, the rat is the preferred species for most assessments of
reproductive toxicity (e.g., based on guidelines for one- and two-generation toxicity
tests, combined repeated-dose with reproductive/developmental toxicity); a rationale
should have been provided for the use of mice in this study. The species and strain (VAF
Crl: Swiss CD-I [ICR]BR outbred albino mice), sex (both), age (e.g., 8 weeks at the
start of Task 1 and 11 weeks at the start of Task 2), and starting body weights of the
animals on the study were reported. Mice were purchased from a commercial source
(Charles River Breeding Laboratories, Inc.).
Metric 14:
Adequacy and Consistency of Animal
High
The following husbandry conditions were reported: temperature, light-dark cycle (14
Husbandry Conditions
hours light/10 hours dark), and food and water availability and were similar for treated
groups of mice and controls. Humidity was not reported.
Metric 15:
Number of Animals per Group
Medium
The number of animals per group was in line with the numbers usually used for studies
of this type. Reproduction studies typically aim to achieve about 20 successful pregnan-
cies per dose group; for some tasks in this study, there were 20 pairs/treatment group,
which resulted in fewer than 20 pregnancies per group (e.g., fertility was 18-19 out of 20
during Task 2). The number of animals per group was adequate to evaluate the outcome
of interest.
Domain 5:
Outcome Assessment
Metric 16:
Outcome Assessment Methodology
High
The outcome analysis was an appropriate method to evaluate the outcome of interest. In
Task 1, body weights were evaluated at days 0, 7, and 14 and water consumption was
evaluated during weeks 1 and 2. In Task 2, body weights were evaluated during weeks
1 (pre-cohabitation), 2 (first week of continuous breeding), 3, 6, 10, and 14; water con-
sumption was evaluated during weeks 2, 6, 10, and 14. Terminal body weights and water
consumption in the week after cohabitation were measured in Task 3. Body weights of
animals in the final litter from Task 2 were measured on postnatal days (PNDs) 0, 4, 7,
14, and 21; terminal body weights and water consumption were also recorded in Task 4.
Metric 17:
Consistency of Outcome Assessment
High
Outcomes were assessed consistently across study groups.
Metric 18:
Sampling Adequacy
Medium
Body weight was evaluated in all animals. Water consumption was measured for males
and females combined during periods in which they shared a cage (e.g., weeks 6, 10,
and 14 of Task 2 and week of Task 4). During cohabitation, the amount of water con-
sumed was estimated by dividing the total consumption by the number of animals per
cage (assumed equal among sexes).
Continued on next page ...
Page 264 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 2 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Nutritional/Metabolic
Body weight and water consumption
Reproductive/Developmental About 35 weeks
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
10603716
Domain
Metric
Rating
Comments
Metric 19:
Metric 20:
Blinding of Assessors
Negative Control Response
N/A
High
Blinding is not applicable to this outcome (which is not subjective).
The biological response of the negative control group was adequate (the controls gained
weight and appeared to drink appropriate amounts of water).
Domain 6: Confounding / Variable Control
Metric 21: Confounding Variables in Test Design Medium
and Procedures
Metric 22: Health Outcomes Unrelated to High
Exposure
Metric 23: Data Presentation and Analysis High
Metric 24: Reporting of Data High
The study did not report all information to determine confounding, but the information
reported did not identify differences.
Details on outcomes unrelated to exposure were reported. The study indicated that,
during quarantine, representative animals were sacrificed and evaluated for antibodies
against mouse viruses and parasites. The health status of sentinel animals maintained in
the same room as treated animals were monitored as well (tested for viral antibodies).
Animals tested negative for viral antibodies throughout the study.
Appropriate statistical analyses were performed at all measured time points.
Body weight and water consumption data were provided in data tables in the body of the
report and/or in the appendices. Data for individual animals (body weight) were reported
in the appendices for some time points (initial and final body weights for Task 2, and at
necropsy for tasks 3 and 4).
Overall Quality Determination
High
Page 265 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 3 of 5
Study Citation: NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Health Reproductive/Developmental
Outcome(s):
Reported Health mating, pregnancy, and fertility, cumulative days to litter, dam weight, mean litters/pair, live pups/litter, proportion of pups born alive, sex of pups, pup
Effect(s): weights, pup survival, estrous cyclicity, sperm parameters (concentration, motility, abnormal sperm), reproductive organ weights (epididymis, testis, cauda
epididymis, prostate, seminal vesicles, ovary) and histology (epididymis, testis, ovary)
Duration: Reproductive/Developmental About 35 weeks
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 10603716
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively: nomenclature: tris(2-
chloroethyl)phosphate and CASRN: 115-96-8. The compound was also identified as
TCEP by gas chromatography.
High The source of the test substance was a manufacturer (Aldrich); a batch/lot number was
indicated (HT0090787).
High TCEP was comprehensively analyzed to determine the purity of the test chemical, which
was indicated to be >98% pure. Observed effects were likely due to the test substance
itself.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High An appropriate control group was used throughout the study (i.e., control mice were
administered the corn oil vehicle only).
N/A Positive controls were not required by study type.
Low The study did not indicate how animals were allocated to study groups. It was men-
tioned that animals were randomly paired for some phases of the experiment.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8:
Metric 9:
Metric 10:
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
Exposure Frequency and Duration
High
Medium
High
High
The test substance was mixed in corn oil; each dose level was independently formulated.
Aliquots of each formulation (including the control) were sent for analysis at various
time points during the study. The stock concentration was 8 mg/mL. Formulation anal-
yses showed that TCEP mixed at this concentration was stable for 3 weeks at room
temperature; dose formulations were prepared at least every three weeks.
Appendix I notes that the time of gavage dosing varied up to 1 hr among doses (one
exception occurred). Other details of exposure administration are incompletely reported
(e.g., gavage volume). Any missing information is unlikely to have a substantial impact
on results (especially since a published protocol that complied to GLP standards was
used).
Doses in mg/kg-day were reported without ambiguity.
The study frequency/duration was adequate to detect effects pertaining to the outcome
of interest. The exposure protocols (duration/timing of exposure) were specifically de-
signed to evaluate reproductive/developmental outcomes.
Continued on next page ...
Page 266 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 3 of 5
... continued from previous page
Study Citation: NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Health Reproductive/Developmental
Outcome(s):
Reported Health mating, pregnancy, and fertility, cumulative days to litter, dam weight, mean litters/pair, live pups/litter, proportion of pups born alive, sex of pups, pup
Effect(s): weights, pup survival, estrous cyclicity, sperm parameters (concentration, motility, abnormal sperm), reproductive organ weights (epididymis, testis, cauda
epididymis, prostate, seminal vesicles, ovary) and histology (epididymis, testis, ovary)
Duration: Reproductive/Developmental About 35 weeks
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 10603716
Domain
Metric
Rating
Comments
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High The dose range-finding (Task 1) and continuous breeding (Task 3) phases of the study
utilized at least 3 dose levels and a concurrent control; the dose intervals were typically
two-fold. The offspring assessment (Task 4) included two dose levels plus the control
owing to there being too few offspring to analyze at the high-dose. Doses were ini-
tially selected (based on the dose range-finding study) to induce some systemic toxicity
without severe toxicity/death at the high-dose (and to allow for the identification of a
NOAEL).
High The study used a route of exposure (oral) that was considered appropriate (i.e., applica-
ble to humans). Analyses of dosing formulations confirmed that the method of exposure
was suited to the test substance (i.e., the test substance was stably mixed with corn oil
for administration via gavage).
Domain 4: Test Animals
Metric 13:
Metric 14:
Test Animal Characteristics
Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium Based on OECD guidelines, the rat is the preferred species for most assessments of
reproductive toxicity (e.g., based on guidelines for one- and two-generation toxicity
tests, combined repeated-dose with reproductive/developmental toxicity); a rationale
should have been provided for the use of mice in this study. The species and strain (VAF
Crl: Swiss CD-I [ICR]BR outbred albino mice), sex (both), age (e.g., 8 weeks at the
start of Task 1 and 11 weeks at the start of Task 2), and starting body weights of the
animals on the study were reported. Mice were purchased from a commercial source
(Charles River Breeding Laboratories, Inc.).
High The following husbandry conditions were reported: temperature, light-dark cycle (14
hours light/10 hours dark), and food and water availability and were similar for treated
groups of mice and controls. Humidity was not reported.
Medium The number of animals per group was in line with the numbers usually used for studies
of this type. Reproduction studies typically aim to achieve about 20 successful pregnan-
cies per dose group; for some tasks in this study, there were 20 pairs/treatment group,
which resulted in fewer than 20 pregnancies per group (e.g., fertility was 18-19 out of 20
during Task 2). The number of animals per group was adequate to evaluate the outcome
of interest.
Domain 5: Outcome Assessment
Metric 16: Outcome Assessment Methodology High The outcome analysis was an appropriate method to evaluate the outcome of interest.
A large number of reproductive/developmental parameters were evaluated in Tasks 2,
3, and 4; the endpoints evaluated were specifically selected to identify sensitive effects
pertaining to this outcome of interest.
Metric 17: Consistency of Outcome Assessment High Outcomes were assessed consistently across study groups.
Continued on next page ...
Page 267 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 3 of 5
... continued from previous page
Study Citation: NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Health Reproductive/Developmental
Outcome(s):
Reported Health mating, pregnancy, and fertility, cumulative days to litter, dam weight, mean litters/pair, live pups/litter, proportion of pups born alive, sex of pups, pup
Effect(s): weights, pup survival, estrous cyclicity, sperm parameters (concentration, motility, abnormal sperm), reproductive organ weights (epididymis, testis, cauda
epididymis, prostate, seminal vesicles, ovary) and histology (epididymis, testis, ovary)
Duration: Reproductive/Developmental About 35 weeks
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 10603716
Domain
Metric
Rating
Comments
Metric 18:
Sampling Adequacy
Medium
Reproductive/developmental parameters were evaluated in all animals that were as-
signed to each task of the study.
Metric 19:
Blinding of Assessors
High
Blinding is not applicable to many of the outcomes (numbers of pups, pup weights,
etc.); however, the study explicitly stated that vaginal cytology and sperm parameters
(evaluated in Tasks 3 and 4) were scored randomly and without knowledge of treatment
group (i.e., blinded). As per guidelines, blinding is not required for initial histology
evaluations.
Metric 20:
Negative Control Response
High
The biological response of the negative control group was adequate (low incidence of
lesions in controls; high fertility in controls, etc.).
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
and Procedures
Medium
The study did not report all information to determine confounding, but the information
reported did not identify differences. In general, the body weights of treated animals
were similar to controls throughout the study.
Metric 22:
Health Outcomes Unrelated to
High
Details on outcomes unrelated to exposure were reported. The study indicated that,
Exposure
during quarantine, representative animals were sacrificed and evaluated for antibodies
against mouse viruses and parasites. The health status of sentinel animals maintained in
the same room as treated animals were monitored as well (tested for viral antibodies).
Animals tested negative for viral antibodies throughout the study.
Metric 23:
Data Presentation and Analysis
High
Appropriate statistical analyses were performed at all measured time points.
Metric 24:
Reporting of Data
High
Reproductive/developmental data (summarized and for individual animals) were pro-
vided in the body of the report and/or the appendices.
Overall Quality Determination
High
Page 268 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 4 of 5
Study Citation: NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Health Hepatic/Liver; Renal/Kidney; Ocular/Sensory; Immune/Hematological;
Outcome(s):
Reported Health Hepatic/Liver: Liver weight and histology (F0 and F1 animals during phases 3 and 4, respectively).; Renal/Kidney: Kidney weight and histology (F0 and
Effect(s): F1 animals during phases 3 and 4, respectively).; Ocular/Sensory: Eye histology (F1 animals in phase 4); Immune/Flematological: Spleen and axillary
lymph nodes histology (F1 animals in phase 4);
Duration: Reproductive/Developmental About 35 weeks
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 10603716
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High All Outcomes: The test substance was identified definitively: nomenclature: tris(2-
chloroethyl)phosphate and CASRN: 115-96-8. The compound was also identified as
TCEP by gas chromatography.
High All Outcomes: The source of the test substance was a manufacturer (Aldrich); a batch/
lot number was indicated (HT0090787).
High All Outcomes: TCEP was comprehensively analyzed to determine the purity of the test
chemical, which was indicated to be >98% pure. Observed effects were likely due to the
test substance itself.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High All Outcomes: An appropriate control group was used throughout the study (i.e., control
mice were administered the corn oil vehicle only).
N/A All Outcomes: Positive controls were not required by study type.
Low All Outcomes: The study did not indicate how animals were allocated to study groups. It
was mentioned that animals were randomly paired for some phases of the experiment.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8:
Metric 9:
Metric 10:
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
Exposure Frequency and Duration
High
Medium
High
High
All Outcomes: The test substance was mixed in corn oil; each dose level was indepen-
dently formulated. Aliquots of each formulation (including the control) were sent for
analysis at various time points during the study. The stock concentration was 8 mg/mL.
Formulation analyses showed that TCEP mixed at this concentration was stable for 3
weeks at room temperature; dose formulations were prepared at least every three weeks.
All Outcomes: Appendix I notes that the time of gavage dosing varied up to 1 hr among
doses (one exception occurred). Other details of exposure administration are incom-
pletely reported (e.g., gavage volume). Any missing information is unlikely to have a
substantial impact on results (especially since a published protocol that complied to GLP
standards was used).
All Outcomes: Doses in mg/kg-day were reported without ambiguity.
All Outcomes: The study frequency/duration was adequate to detect effects pertaining to
the outcome of interest.
Continued on next page ...
Page 269 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 4 of 5
... continued from previous page
Study Citation: NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Health Hepatic/Liver; Renal/Kidney; Ocular/Sensory; Immune/Hematological;
Outcome(s):
Reported Health Hepatic/Liver: Liver weight and histology (F0 and F1 animals during phases 3 and 4, respectively).; Renal/Kidney: Kidney weight and histology (F0 and
Effect(s): F1 animals during phases 3 and 4, respectively).; Ocular/Sensory: Eye histology (F1 animals in phase 4); Immune/Flematological: Spleen and axillary
lymph nodes histology (F1 animals in phase 4);
Duration: Reproductive/Developmental About 35 weeks
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 10603716
Domain
Metric
Rating
Comments
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High All Outcomes: The dose range-finding (Task 1) and continuous breeding (Task 3) phases
of the study utilized at least 3 dose levels and a concurrent control; the dose intervals
were typically two-fold. The offspring assessment (Task 4) included two dose levels
plus the control owing to there being too few offspring to analyze at the high-dose.
Doses were initially selected (based on the dose range-finding study) to induce some
systemic toxicity without severe toxicity/death at the high-dose (and to allow for the
identification of a NOAEL).
High All Outcomes: The study used a route of exposure (oral) that was considered appropriate
(i.e., applicable to humans). Analyses of dosing formulations confirmed that the method
of exposure was suited to the test substance (i.e., the test substance was stably mixed
with corn oil for administration via gavage).
Domain 4: Test Animals
Metric 13:
Test Animal Characteristics
Metric 14:
Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium All Outcomes: Based on OECD guidelines, the rat is the preferred species for most as-
sessments of reproductive toxicity (e.g., based on guidelines for one- and two-generation
toxicity tests, combined repeated-dose with reproductive/developmental toxicity); a
rationale should have been provided for the use of mice in this study. The species and
strain (VAF Crl: Swiss CD-I [ICR]BR outbred albino mice), sex (both), age (e.g.,
8 weeks at the start of Task 1 and 11 weeks at the start of Task 2), and starting body
weights of the animals on the study were reported. Mice were purchased from a com-
mercial source (Charles River Breeding Laboratories, Inc.).
High All Outcomes: The following husbandry conditions were reported: temperature, light-
dark cycle (14 hours light/10 hours dark), and food and water availability and were
similar for treated groups of mice and controls. Humidity was not reported.
Medium All Outcomes: The number of animals per group was in line with the numbers usually
used for studies of this type. Reproduction studies typically aim to achieve about 20
successful pregnancies per dose group; for some tasks in this study, there were 20 pairs/
treatment group, which resulted in fewer than 20 pregnancies per group (e.g., fertility
was 18-19 out of 20 during Task 2). The number of animals per group was adequate to
evaluate the outcome of interest.
Domain 5: Outcome Assessment
Continued on next page ...
Page 270 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 4 of 5
... continued from previous page
Study Citation: NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Health Hepatic/Liver; Renal/Kidney; Ocular/Sensory; Immune/Hematological;
Outcome(s):
Reported Health Hepatic/Liver: Liver weight and histology (F0 and F1 animals during phases 3 and 4, respectively).; Renal/Kidney: Kidney weight and histology (F0 and
Effect(s): F1 animals during phases 3 and 4, respectively).; Ocular/Sensory: Eye histology (F1 animals in phase 4); Immune/Flematological: Spleen and axillary
lymph nodes histology (F1 animals in phase 4);
Duration: Reproductive/Developmental About 35 weeks
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 10603716
Domain
Metric
Rating
Comments
Metric 16: Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Metric 18: Sampling Adequacy
Metric 19: Blinding of Assessors
Metric 20: Negative Control Response
Medium Hepatic/Liver: The outcome analysis partially addressed the outcome of interest. Liver
weight and histology were evaluated in F0 and F1 animals at the end of Tasks 3 and
4, respectively (only high-dose animals and controls in Task 4). No other (potentially
more sensitive) measures of liver toxicity (e.g., hematology or clinical chemistry pa-
rameters) were evaluated in the study.; Renal/Kidney: The outcome analysis partially
addressed the outcome of interest. Kidney weight and histology were evaluated in F0
and F1 animals at the end of Tasks 3 and 4, respectively (only high-dose animals and
controls in Task 4). No other (potentially more sensitive) measures of renal toxicity
(e.g., clinical chemistry or urinalysis parameters) were evaluated in the study.; Ocular/
Sensory: The outcome analysis partially addressed the outcome of interest. Eye his-
tology was evaluated in F1 animals at the end of Task 4 (only high-dose animals and
controls). No other measures of ocular toxicity were evaluated in the study, and the eyes
of F0 animals sacrificed at the end of Task 3 were also not evaluated histologically.; Im-
mune/Flematological: The outcome analysis partially addressed the outcome of interest.
Spleen/lymph node histology was evaluated in F1 animals at the end of Task 4 (only
high-dose animals and controls). No other measures of immunotoxicity were evaluated
in the study, and the spleen/lymph nodes of F0 animals sacrificed at the end of Task 3
were also not evaluated histologically.
High All Outcomes: Outcomes were assessed consistently across study groups.
High Hepatic/Liver: Liver weight was assessed in all animals on the study; liver histology
was assessed in all animals in Task 3 and in control and high-dose animals in Task 4.;
Renal/Kidney: Kidney weight was assessed in all animals on the study; kidney histology
was assessed in all animals in Task 3 and in control and high-dose animals in Task 4.;
Ocular/Sensory: Eye histology was assessed in control and high-dose animals in Task 4.;
Immune/Hematological: Spleen/axillary lymph nodes histology was assessed in control
and high-dose animals in Task 4.
N/A Hepatic/Liver: Blinding is not applicable to liver weight (which is not subjective);
guidelines indicate that blinding is not required for initial histological evaluations.;
Renal/Kidney: Blinding is not applicable to kidney weight (which is not subjective);
guidelines indicate that blinding is not required for initial histological evaluations.; Oc-
ular/Sensory: Guidelines indicate that blinding is not required for initial histological
evaluations.; Immune/Hematological: Guidelines indicate that blinding is not required
for initial histological evaluations.
High All Outcomes: The biological response of the negative control group was adequate (e.g.,
the incidence of lesions was low in controls).
Domain 6: Confounding / Variable Control
Continued on next page .
Page 271 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 4 of 5
... continued from previous page
Study Citation: NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Health Hepatic/Liver; Renal/Kidney; Ocular/Sensory; Immune/Hematological;
Outcome(s):
Reported Health Hepatic/Liver: Liver weight and histology (F0 and F1 animals during phases 3 and 4, respectively).; Renal/Kidney: Kidney weight and histology (F0 and
Effect(s): F1 animals during phases 3 and 4, respectively).; Ocular/Sensory: Eye histology (F1 animals in phase 4); Immune/Flematological: Spleen and axillary
lymph nodes histology (F1 animals in phase 4);
Duration: Reproductive/Developmental About 35 weeks
Chemical: Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
HERO ID: 10603716
Domain
Metric
Rating
Comments
Metric 21:
Metric 22:
Metric 23:
Metric 24:
Confounding Variables in Test Design Medium
and Procedures
Flealth Outcomes Unrelated to
Exposure
Data Presentation and Analysis
Reporting of Data
High
High
High
All Outcomes: The study did not report all information to determine confounding, but
the information reported did not identify differences. In general, the body weights of
treated animals were similar to controls throughout the study.
All Outcomes: Details on outcomes unrelated to exposure were reported. The study
indicated that, during quarantine, representative animals were sacrificed and evaluated
for antibodies against mouse viruses and parasites. The health status of sentinel animals
maintained in the same room as treated animals were monitored as well (tested for viral
antibodies). Animals tested negative for viral antibodies throughout the study.
All Outcomes: Appropriate statistical analyses were performed (or could be performed)
at all measured time points.
Hepatic/Liver: Liver data were provided in the study report. Liver data for individual an-
imals were also reported in the appendices.; Renal/Kidney: Kidney data were provided
in the study report. Kidney data for individual animals were also reported in the appen-
dices.; Ocular/Sensory: Eye histology data (summarized and for individual animals)
were provided in the study report and/or appendices.; Immune/Hematological: Spleen/
lymph nodes histology data (summarized and for individual animals) were provided in
the study report and/or appendices.
Overall Quality Determination
High
Page 272 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 5 of 5
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Neurological/Behavioral
Brain histology (F0 and F1 animals during phases 3 and 4, respectively).
Reproductive/Developmental About 35 weeks
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
10603716
Domain
Metric
Rating
Comments
Domain 1: Test Substance
Metric 1: Test Substance Identity
Metric 2: Test Substance Source
Metric 3: Test Substance Purity
High The test substance was identified definitively: nomenclature: tris(2-
chloroethyl)phosphate and CASRN: 115-96-8. The compound was also identified as
TCEP by gas chromatography.
High The source of the test substance was a manufacturer (Aldrich); a batch/lot number was
indicated (HT0090787).
High TCEP was comprehensively analyzed to determine the purity of the test chemical, which
was indicated to be >98% pure. Observed effects were likely due to the test substance
itself.
Domain 2: Test Design
Metric 4: Negative and Vehicle Controls
Metric 5: Positive Controls
Metric 6: Randomized Allocation of Animals
High An appropriate control group was used throughout the study (i.e., control mice were
administered the corn oil vehicle only).
N/A Positive controls were not required by study type.
Low The study did not indicate how animals were allocated to study groups. It was men-
tioned that animals were randomly paired for some phases of the experiment.
Domain 3: Exposure Characterization
Metric 7: Preparation and Storage of Test
Substance
Metric 8:
Metric 9:
Metric 10:
Consistency of Exposure
Administration
Reporting of Doses/Concentrations
Exposure Frequency and Duration
High
Medium
High
Medium
The test substance was mixed in corn oil; each dose level was independently formulated.
Aliquots of each formulation (including the control) were sent for analysis at various
time points during the study. The stock concentration was 8 mg/mL. Formulation anal-
yses showed that TCEP mixed at this concentration was stable for 3 weeks at room
temperature; dose formulations were prepared at least every three weeks.
Appendix I notes that the time of gavage dosing varied up to 1 hr among doses (one
exception occurred). Other details of exposure administration are incompletely reported
(e.g., gavage volume). Any missing information is unlikely to have a substantial impact
on results (especially since a published protocol that complied to GLP standards was
used).
Doses in mg/kg-day were reported without ambiguity.
The study frequency/duration was generally adequate to detect effects pertaining to the
outcome of interest but because the test substance has an effect on cholinesterase, the
study would have been more robust if it tested animals postnatally for this activity.
Continued on next page ...
Page 273 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 5 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Neurological/Behavioral
Brain histology (F0 and F1 animals during phases 3 and 4, respectively).
Reproductive/Developmental About 35 weeks
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
10603716
Domain
Metric
Rating
Comments
Metric 11: Number of Exposure Groups and
Dose/Concentration Spacing
Metric 12: Exposure Route and Method
High The dose range-finding (Task 1) and continuous breeding (Task 3) phases of the study
utilized at least 3 dose levels and a concurrent control; the dose intervals were typically
two-fold. The offspring assessment (Task 4) included two dose levels plus the control
owing to there being too few offspring to analyze at the high-dose. Doses were ini-
tially selected (based on the dose range-finding study) to induce some systemic toxicity
without severe toxicity/death at the high-dose (and to allow for the identification of a
NOAEL).
High The study used a route of exposure (oral) that was considered appropriate (i.e., applica-
ble to humans). Analyses of dosing formulations confirmed that the method of exposure
was suited to the test substance (i.e., the test substance was stably mixed with corn oil
for administration via gavage).
Domain 4: Test Animals
Metric 13:
Metric 14:
Test Animal Characteristics
Adequacy and Consistency of Animal
Husbandry Conditions
Metric 15: Number of Animals per Group
Medium Based on OECD guidelines, the rat is the preferred species for most assessments of
reproductive toxicity (e.g., based on guidelines for one- and two-generation toxicity
tests, combined repeated-dose with reproductive/developmental toxicity); a rationale
should have been provided for the use of mice in this study. The species and strain (VAF
Crl: Swiss CD-I [ICR]BR outbred albino mice), sex (both), age (e.g., 8 weeks at the
start of Task 1 and 11 weeks at the start of Task 2), and starting body weights of the
animals on the study were reported. Mice were purchased from a commercial source
(Charles River Breeding Laboratories, Inc.).
High The following husbandry conditions were reported: temperature, light-dark cycle (14
hours light/10 hours dark), and food and water availability and were similar for treated
groups of mice and controls. Humidity was not reported.
Medium The number of animals per group was in line with the numbers usually used for studies
of this type. Reproduction studies typically aim to achieve about 20 successful pregnan-
cies per dose group; for some tasks in this study, there were 20 pairs/treatment group,
which resulted in fewer than 20 pregnancies per group (e.g., fertility was 18-19 out of 20
during Task 2). The number of animals per group was adequate to evaluate the outcome
of interest.
Domain 5: Outcome Assessment
Metric 16:
Outcome Assessment Methodology
Metric 17: Consistency of Outcome Assessment
Medium The outcome analysis partially addressed the outcome of interest. Brain histology was
evaluated in F0 and F1 animals at the end of Tasks 3 and 4, respectively (only high-dose
animals and controls in Task 4). No other measures of neurotoxicity were evaluated
in the study. In particular brain weights were not evaluated nor were changes in serum
cholinesterase.
High Outcomes were assessed consistently across study groups.
Continued on next page ...
Page 274 of 275
-------
Tris(2-chloroethyl) phosphate (TCEP)
PUBLIC RELEASE DRAFT - DO NOT CITE OR QUOTE
December 2023
Human Health Hazard Animal Toxicology Evaluation
HERO ID: 10603716 Table: 5 of 5
... continued from previous page
Study Citation:
Health
Outcome(s):
Reported Health
Effect(s):
Duration:
Chemical:
HERO ID:
NTP, (1991). Final report on the reproductive toxicity of tris(2-chloroethyl) phosphate in CD-I Swiss mice.
Neurological/Behavioral
Brain histology (F0 and F1 animals during phases 3 and 4, respectively).
Reproductive/Developmental About 35 weeks
Tris(2-chloroethyl) phosphate (TCEP)- Parent compound
10603716
Domain
Metric
Rating
Comments
Metric 18:
Sampling Adequacy
High
Brain histology was assessed in all animals in Task 3 and in control and high-dose ani-
mals in Task 4.
Metric 19:
Blinding of Assessors
N/A
Guidelines indicate that blinding is not required for initial histological evaluations.
Metric 20:
Negative Control Response
High
The biological response of the negative control group was adequate (e.g., the incidence
of lesions was low in controls).
Domain 6: Confounding / Variable Control
Metric 21:
Confounding Variables in Test Design
Medium
The study did not report all information to determine confounding, but the information
and Procedures
reported did not identify differences. In general, the body weights of treated animals
were similar to controls throughout the study.
Metric 22:
Health Outcomes Unrelated to
High
Details on outcomes unrelated to exposure were reported. The study indicated that,
Exposure
during quarantine, representative animals were sacrificed and evaluated for antibodies
against mouse viruses and parasites. The health status of sentinel animals maintained in
the same room as treated animals were monitored as well (tested for viral antibodies).
Animals tested negative for viral antibodies throughout the study.
Metric 23:
Data Presentation and Analysis
High
Appropriate statistical analyses were performed (or could be performed) at all measured
time points.
Metric 24:
Reporting of Data
High
Brain histology data (summarized and for individual animals) were provided in the
study report and/or appendices.
Overall Quality Determination
High
Page 275 of 275
------- |