TSCA Section 5(a)(3) Determination for Premanufacture Notice (PMN) P-18-0376

Number: P-18-0376

TSCA Section 5(a)(3) Determination: The chemical substance is not likely to present an
unreasonable risk (5(a)(3)(C))

Chemical Name:

Generic: Thiosulfuric acid, aminoalkyl ester

Conditions of Use (intended, known, or reasonably foreseen)1:

Intended conditions of use (specific): Import for use in rubber products to improve physical

properties, consistent with the manufacturing, processing, use, distribution, and disposal
information described in the PMN.

Known conditions of use: Applying such factors as described in footnote 1, EPA evaluated
whether there are known conditions of use and found, based on another TSCA
submission, that the substance is known to be used for the same use as intended in the
PMN.

Reasonably foreseen conditions of use: Applying such factors as described in footnote 1, EPA
evaluated whether there are reasonably foreseen conditions of use and found none.

Summary: The chemical substance is not likely to present an unreasonable risk of injury to
health or the environment, without consideration of costs or other nonrisk factors, including an
unreasonable risk to a potentially exposed or susceptible subpopulation identified as relevant by
the Administrator under the conditions of use, based on the risk assessment presented below.
Although EPA estimated that the new chemical substance could be very persistent, the substance
has low potential for bioaccumulation, such that repeated exposures are not expected to cause
food-chain effects via accumulation in exposed organisms. Based on test data on the new
chemical substance, EPA estimates that the new chemical substance has low environmental
hazard and potential for the following human health hazards: eye irritation, skin irritation, skin
sensitization, reproductive toxicity and specific target organ toxicity. EPA concludes that the

1 Under TSCA § 3(4), the term "conditions of use" means "the circumstances, as determined by the Administrator,
under which a chemical substance is intended, known, or reasonably foreseen to be manufactured, processed,
distributed in commerce, used, or disposed of." In general, EPA considers the intended conditions of use of a new
chemical substance to be those identified in the section 5(a) notification. Known conditions of use include activities
within the United States that result from manufacture that is exempt from PMN submission requirements.

Reasonably foreseen conditions of use are future circumstances, distinct from known or intended conditions of use,
under which the Administrator expects the chemical substance to be manufactured, processed, distributed, used, or
disposed of. The identification of "reasonably foreseen" conditions of use will necessarily be a case-by-case
determination and will be highly fact-specific. Reasonably foreseen conditions of use will not be based on
hypotheticals or conjecture. EPA's identification of conditions of use includes the expectation of compliance with
federal and state laws, such as worker protection standards or disposal restrictions, unless case-specific facts indicate
otherwise. Accordingly, EPA will apply its professional judgment, experience, and discretion when considering such
factors as evidence of current use of the new chemical substance outside the United States, evidence that the PMN
substance is sufficiently likely to be used for the same purposes as existing chemical substances that are structurally
analogous to the new chemical substance, and conditions of use identified in an initial PMN submission that the
submitter omits in a revised PMN. The sources EPA uses to identify reasonably foreseen conditions of use include
searches of internal confidential EPA PMN databases (containing use information on analogue chemicals), other
U.S. government public sources, the National Library of Medicine's Hazardous Substances Data Bank (HSDB), the
Chemical Abstract Service STN Platform, REACH Dossiers, technical encyclopedias (e.g., Kirk-Othmer and
Ullmann), and Internet searches.

1

-------
TSCA Section 5(a)(3) Determination for Premanufacture Notice (PMN) P-18-0376

new chemical substance is not likely to present an unreasonable risk under the conditions of use.

Fate: Environmental fate is the determination of which environmental compartment(s) a
chemical moves to, the expected residence time in the environmental compartment(s) and
removal and degradation processes. Environmental fate is an important factor in determining
exposure and thus in determining whether a chemical may present an unreasonable risk. EPA
estimated physical/chemical and fate properties of the new chemical substance using data
submitted for the new chemical substance and EPI (Estimation Program Interface) Suite™
(http://www.epa.gov/tsca-screening-tools/epi-suitetm-estimation-program-interface). In
wastewater treatment, the new chemical substance is expected to be removed with an efficiency
of 0% due to low biodegradability, low sorption, and low stripping. Removal of the new
chemical substance by biodegradation is negligible. Sorption of the new chemical substance to
sludge, soil, and sediment is expected to be low. Migration of the new chemical substance to
groundwater is expected to be rapid due to low sorption to soil and sediment. Due to low
estimated vapor pressure and Henry's law constant, the new chemical substance is expected to
undergo negligible volatilization to air. Overall, these estimates indicate that the new chemical
substance has low potential to volatilize to air and has high potential to migrate to groundwater.

Persistence : Persistence is relevant to whether a new chemical substance is likely to present an
unreasonable risk because chemicals that are not degraded in the environment at rates that
prevent substantial buildup in the environment, and thus increase potential for exposure, may
present a risk if the substance presents a hazard to human health or the environment. EPA
estimated degradation half-lives of the new chemical substance using data submitted for the new
chemical substance. EPA estimated that the new chemical substance's aerobic and anaerobic
biodegradation half-lives are > 6 months. These estimates indicate that the new chemical
substance may be very persistent in aerobic environments (e.g., surface water) and anaerobic
environments (e.g., sediment).

-2

Bioaccumulation : Bioaccumulation is relevant to whether a new chemical substance is likely
to present an unreasonable risk because substances that bioaccumulate in aquatic and/or
terrestrial species pose the potential for elevated exposures to humans and other organisms via
food chains. EPA estimated the potential for the new chemical substance to bioaccumulate using
data submitted for the new chemical substance. EPA estimated that the new chemical substance
has low bioaccumulation potential based on submitted data (bioconcentration factor = < 5.7
[measured]). Although EPA estimated that the new chemical substance could be very persistent,

2	Persistence: A chemical substance is considered to have limited persistence if it has a half-life in water, soil or
sediment of less than 2 months or there are equivalent or analogous data. A chemical substance is considered to be
persistent if it has a half-life in water, soil or sediments of greater than 2 months but less than or equal to 6 months
or if there are equivalent or analogous data. A chemical substance is considered to be very persistent if it has a half-
life in water, soil or sediments of greater than 6 months or there are equivalent or analogous data. (64 FR 60194;
November 4, 1999)

3	Bioaccumulation: A chemical substance is considered to have a low potential for bioaccumulation if there are
bioconcentration factors (BCF) or bioaccumulation factors (BAF) of less than 1,000 or there are equivalent or
analogous data. A chemical substance is considered to be bioaccumulative if there are BCFs or BAFs of 1,000 or
greater and less than or equal to 5,000 or there are equivalent or analogous data. A chemical substance is considered
to be very bioaccumulative if there are BCFs or BAFs of 5,000 or greater or there are equivalent or analogous data.
(64 FR 60194; November 4 1999)

2

-------
TSCA Section 5(a)(3) Determination for Premanufacture Notice (PMN) P-18-0376

the substance has low potential for bioaccumulation, such that repeated exposures are not
expected to cause food-chain effects via accumulation in exposed organisms.

Human Health Hazard4: Human health hazard is relevant to whether a new chemical substance
is likely to present an unreasonable risk because the significance of the risk is dependent upon
both the hazard (or toxicity) of the chemical substance and the extent of exposure to the
substance. EPA estimated the human health hazard of this new chemical substance based on its
estimated physical/chemical properties, available data on the new chemical substance, and other
structural information. Absorption is expected to be poor when neat and moderate when in
solution through skin, and poor through the gastrointestinal (GI) tract and good through the lungs
based on physical/chemical properties. Test data on the new chemical substance indicate it is
irritating to the eye, minimally irritating to skin; positive for skin sensitization in one test and
negative in another; negative for genotoxicity and has low acute toxicity via oral, inhalation and
dermal routes of exposure. In an OECD 421 Reproductive/Developmental Toxicity Screening
Test, systemic, reproductive and developmental effects were identified as hazards. EPA
identified a no-observed-adverse-effect-level (NOAEL) of 60 mg/kg-bw/day based on changes in
thyroid hormone levels in offspring, which was used to derive exposure route- and population-
specific points of departure for quantitative risk assessment. EPA qualitatively evaluated
irritation and sensitization effects.

Environmental Hazard5: Environmental hazard is relevant to whether a new chemical
substance is likely to present unreasonable risk because the significance of the risk is dependent
upon both the hazard (or toxicity) of the chemical substance and the extent of exposure to the

4	A chemical substance is considered to have low human health hazard if effects are observed in animal studies with
a No Observed Adverse Effect Level (NOAEL) equal to or greater than 1,000 mg/kg/day or if there are equivalent
data on analogous chemical substances; a chemical substance is considered to have moderate human health hazard if
effects are observed in animal studies with a NOAEL less than 1,000 mg/kg/day or if there are equivalent data on
analogous chemical substances; a chemical substance is considered to have high human health hazard if there is
evidence of adverse effects in humans or conclusive evidence of severe effects in animal studies with a NOAEL of
less than or equal to 10 mg/kg/day or if there are equivalent data on analogous chemical substances. EPA may also
use Benchmark Dose Levels (BMDL) derived from benchmark dose (BMD) modeling as points of departure for
toxic effects. See https://www.epa.gov/bmds/what-benchmark-dose-software-bmds. Using this approach, a BMDL
is associated with a benchmark response, for example a 5 or 10 % incidence of effect. The aforementioned
characterizations of hazard (low, medium, high) would also apply to BMDLs. In the absence of animal data on a
chemical or analogous chemical substance, EPA may use other data or information such as from in vitro assays,
chemical categories (e.g., Organization for Economic Co-operation and Development, 2014 Guidance on Grouping
of Chemicals, Second Edition. ENV/JM/MONO(2014)4. Series on Testing & Assessment No. 194. Environment
Directorate, Organization for Economic Co-operation and Development, Paris, France.

(http://www.oecd.org/officialdocuments/publicdisplavdocumentpdf/?cote=env/im/mono(2014)4&doclanguage=en)).
structure-activity relationships, and/or structural alerts to support characterizing human health hazards.

5	A chemical substance is considered to have low ecotoxicity hazard if the Fish, Daphnid and Algae LC50 values are
greater than 100 mg/L, or if the Fish and Daphnid chronic values (ChVs) are greater than 10.0 mg/L, or there are not
effects at saturation (occurs when water solubility of a chemical substance is lower than an effect concentration), or
the log Kow value exceeds QSAR cut-offs. A chemical substance is considered to have moderate ecotoxicity hazard
if the lowest of the Fish, Daphnid or Algae LC50s is greater than 1 mg/L and less than 100 mg/L, or where the Fish
or Daphnid ChVs are greater than 0.1 mg/L and less than 10.0 mg/L. A chemical substance is considered to have
high ecotoxicity hazard, or if either the Fish, Daphnid or Algae LC50s are less than 1 mg/L, or any Fish or Daphnid
ChVs is less than 0.1 mg/L (Sustainable Futures https://www.epa.gov/sustainable-futures/sustainable-futures-p2-
framework-manual).

3

-------
TSCA Section 5(a)(3) Determination for Premanufacture Notice (PMN) P-18-0376

substance. EPA determined the environmental hazard for this new chemical substance based on
acute toxicity data submitted for the new chemical substance. The substance falls within the
TSCA New Chemicals Category of Aliphatic Amines.6 Based on experimental test data, acute
toxicity values for fish, aquatic invertebrates, and algae are >98.2 mg/L, >100 mg/L, and >100
mg/L, respectively. Based on experimental test data, chronic toxicity values for fish, aquatic
invertebrates, and algae are >10 mg/L (ACR of 10), >10 mg/L (ACR of 10), and 100 mg/L,
respectively. These toxicity values indicate that the new chemical substance is expected to have
low environmental hazard. Application of assessment factors of 5 and 10 to acute and chronic
toxicity values, respectively, results in acute and chronic concentrations of concern of 20 mg/L
(20,000 ppb) and 1 mg/L (1,000 ppb), respectively.

Exposure: The exposure to a new chemical substance is potentially relevant to whether a new
chemical substance is likely to present unreasonable risks because the significance of the risk is
dependent upon both the hazard (or toxicity) of the chemical substance and the extent of
exposure to the substance.

EPA estimates occupational exposure and environmental release of the new chemical substance
under the intended conditions of use described in the PMN using ChemSTEER (Chemical
Screening Tool for Exposures and Environmental Releases; https://www.epa.gov/tsca-screening-
tools/chemsteer-chemical-screening-tool-exposures-and-environmental-releases). EPA uses
EFAST (the Exposure and Fate Assessment Screening Tool; https://www.epa.gov/tsca-
screening-tools/e-fast-exposure-and-fate-assessment-screening-tool-version-2014) to estimate
general population, consumer, and environmental exposures.

EPA considers workers to be a potentially exposed or susceptible subpopulation (PESS) on the
basis of greater exposure potential compared to the general population. EPA also considers PESS
in conducting general population drinking water exposures by evaluating risks associated with
water intake rates for multiple age groups, ranging from infants to adults. EPA considers
consumers of specific products to be a potentially exposed or susceptible subpopulation on the
basis of greater exposure potential compared to the general population who do not use specific
products.

For this new chemical assessment, EPA assessed worker exposure via the inhalation and dermal
routes. Releases to air and landfill were estimated. No releases to water were expected. Exposure
to the general population was assessed via groundwater impacted by landfill leaching. Exposure
to the general population was not assessed via inhalation because release to air is expected to be
negligible (below modeling thresholds). Consumer exposures were not assessed because
consumer uses were not identified as conditions of use.

Risk Characterization: EPA applies a margin of exposure approach to calculate potential
human health risks of new chemicals. A benchmark (acceptable) margin of exposure is derived
by applying uncertainty factors for the following types of extrapolations: intra-species
extrapolation (UFH = 10 to account for variation in sensitivity among the human population),

6 TSCA New Chemicals Program (NCP) Chemical Categories, https://www.epa.gov/reviewing-new-chemicals-
under-toxic-substances-control-act-tsca/chemical-categories-used-review-new.

4

-------
TSCA Section 5(a)(3) Determination for Premanufacture Notice (PMN) P-18-0376

inter-species extrapolation (UFa = 10 to account for extrapolating from experimental animals to
humans) and LOAEL-to-NOAEL extrapolation (UFL = 10 to account for using a LOAEL when
a NOAEL is not available). Hence, in the New Chemicals Program, a benchmark MOE is
typically 100 and 1,000 when NOAELs and LOAELs, respectively, are used to identify hazard.
When allometric scaling or pharmacokinetic modeling is used to derive an effect level, the UFh
may be reduced to 3, for a benchmark MOE of 30. The benchmark MOE is used to compare to
the MOE calculated by comparing the toxicity NOAEL or LOAEL to the estimated exposure
concentrations. When the calculated MOE is equal to or exceeds the benchmark MOE, the new
chemical substance is not likely to present an unreasonable risk. EPA assesses risks to workers
considering engineering controls described in the PMN but in the absence of personal protective
equipment (PPE) such as gloves and respirators. If risks are preliminarily identified, EPA then
considers whether the risks would be mitigated by the use of PPE (e.g., impervious gloves,
respirator).

Risks to human health for the new chemical substance were evaluated using the route-specific
effect levels (i.e., NOAEL) described above. Risks were identified for workers for
developmental effects via inhalation exposure to total dust based on quantitative hazard data for
the new chemical substance (MOEinhaiation = 87; Benchmark MOE = 100; Fold factor = 1.1).

Risks were identified for workers for developmental toxicity via dermal contact based on
quantitative hazard data for the new chemical substance (MOEdermai = 3; Benchmark MOE =
100). Skin, eye, and respiratory tract irritation and skin sensitization hazards to workers were
identified based on submitted test data and information provided in the SDS. Risks for these
endpoints were not quantified due to a lack of dose-response for these hazards. However, risks
will be mitigated if exposures are controlled by the use of appropriate PPE, including impervious
gloves, eye protection, and a NIOSH-approved respirator with an assigned protection factor
(APF) of at least 10. EPA expects that employers will require that workers will use appropriate
PPE consistent with the SDS prepared by the new chemical submitter, in a manner adequate to
protect them.

Risks were not identified for the general population for developmental toxicity via ground water
(impacted by landfill leachate) based on quantitative hazard data for new chemical substance
(Groundwater MOE > 200,000; Benchmark MOE = 100). Risks were not assessed for the
general population via ingestion of drinking water, fish ingestion and inhalation of stack/fugitive
air because predicted environmental releases are expected to be negligible (below modeling
thresholds). Sensitization and irritation hazards to the general population are not expected via
drinking water ingestion due to no release of the new chemical substance to the surface water.
Risks to consumers were not evaluated because consumer uses were not identified as conditions
of use.

Risks to the environment were not identified based on low hazard.

Because worker exposures can be controlled by PPE, no unreasonable risks to the general
population or environment were identified, and there are no expected consumer exposures, EPA
has determined that the new chemical substance is not likely to present unreasonable risk to
human health or the environment under the conditions of use.

5

-------
TSCA Section 5(a)(3) Determination for Premanufacture Notice (PMN) P-18-0376

4/2/2020		IsL

Date:	Tala R. Henry, Ph.D.

Deputy Director for Programs

Office of Pollution Prevention and Toxics

6

-------