United States
Environmental Protection
1=1 m m Agency
EPA/690/R-12/01 IF
Final
6-21-2012
Provisional Peer-Reviewed Toxicity Values for
2,2-Dichloropropane
(CASRN 594-20-7)
Superfund Health Risk Technical Support Center
National Center for Environmental Assessment
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268

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AUTHORS, CONTRIBUTORS, AND REVIEWERS
CHEMICAL MANAGER
Chris Cubbison, PhD (Mentor)
Custodio V. Muianga, PhD, MPH (Student Services Contractor)
National Center for Environmental Assessment, Cincinnati, OH
DRAFT DOCUMENT PREPARED BY
National Center for Environmental Assessment, Cincinnati, OH
This document was externally peer reviewed under contract to
Eastern Research Group, Inc.
110 Hartwell Avenue
Lexington, MA 02421-3136
Questions regarding the contents of this document may be directed to the U.S. EPA Office of
Research and Development's National Center for Environmental Assessment, Superfund Health
Risk Technical Support Center (513-569-7300).

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TABLE OF CONTENTS
COMMONLY USED ABBREVIATIONS	ii
BACKGROUND	1
DISCLAIMERS	1
QUESTIONS REGARDING PPRTVS	 1
INTRODUCTION	2
REVIEW OF POTENTIALLY RELEVANT DATA (CANCER AND NONCANCER)	3
DERIVATION 01 PROVISIONAL VALUES	3
CANCER WEIGHT-OF-EVIDENCE (WOE) DESCRIPTOR	3
MODE-OF-ACTION (MOA) DISCI SSION	4
REFERENCES	4
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COMMONLY USED ABBREVIATIONS
BMC
benchmark concentration
BMCL
benchmark concentration lower bound 95% confidence interval
BMD
benchmark dose
BMDL
benchmark dose lower bound 95% confidence interval
HEC
human equivalent concentration
HED
human equivalent dose
IUR
inhalation unit risk
LOAEL
lowest-observed-adverse-effect level
LOAELadj
LOAEL adjusted to continuous exposure duration
LOAELhec
LOAEL adjusted for dosimetric differences across species to a human
NOAEL
no-ob served-adverse-effect level
NOAELadj
NOAEL adjusted to continuous exposure duration
NOAELhec
NOAEL adjusted for dosimetric differences across species to a human
NOEL
no-ob served-effect level
OSF
oral slope factor
p-IUR
provisional inhalation unit risk
POD
point of departure
p-OSF
provisional oral slope factor
p-RfC
provisional reference concentration (inhalation)
p-RfD
provisional reference dose (oral)
RfC
reference concentration (inhalation)
RfD
reference dose (oral)
UF
uncertainty factor
UFa
animal-to-human uncertainty factor
UFC
composite uncertainty factor
UFd
incomplete-to-complete database uncertainty factor
UFh
interhuman uncertainty factor
UFl
LOAEL-to-NOAEL uncertainty factor
UFS
subchronic-to-chronic uncertainty factor
WOE
weight of evidence
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PROVISIONAL PEER-REVIEWED TOXICITY VALUES
2,2-DICHLOROPROPANE (CASRN 594-20-7)
BACKGROUND
A Provisional Peer-Reviewed Toxicity Value (PPRTV) is defined as a toxicity value
derived for use in the Superfund Program. PPRTVs are derived after a review of the relevant
scientific literature using established Agency guidance on human health toxicity value
derivations. All PPRTV assessments receive internal review by a standing panel of National
Center for Environment Assessment (NCEA) scientists and an independent external peer review
by three scientific experts.
The purpose of this document is to provide support for the hazard and dose-response
assessment pertaining to chronic and subchronic exposures to substances of concern, to present
the major conclusions reached in the hazard identification and derivation of the PPRTVs, and to
characterize the overall confidence in these conclusions and toxicity values. It is not intended to
be a comprehensive treatise on the chemical or toxicological nature of this substance.
The PPRTV review process provides needed toxicity values in a quick turnaround
timeframe while maintaining scientific quality. PPRTV assessments are updated approximately
on a 5-year cycle for new data or methodologies that might impact the toxicity values or
characterization of potential for adverse human health effects and are revised as appropriate. It is
important to utilize the PPRTV database flittp://hhpprtv.ornl.gov) to obtain the current
information available. When a final Integrated Risk Information System (IRIS) assessment is
made publicly available on the Internet (www.epa.eov/iris). the respective PPRTVs are removed
from the database.
DISCLAIMERS
The PPRTV document provides toxicity values and information about the adverse effects
of the chemical and the evidence on which the value is based, including the strengths and
limitations of the data. All users are advised to review the information provided in this
document to ensure that the PPRTV used is appropriate for the types of exposures and
circumstances at the site in question and the risk management decision that would be supported
by the risk assessment.
Other U.S. Environmental Protection Agency (EPA) programs or external parties who
may choose to use PPRTVs are advised that Superfund resources will not generally be used to
respond to challenges, if any, of PPRTVs used in a context outside of the Superfund program.
QUESTIONS REGARDING PPRTVS
Questions regarding the contents and appropriate use of this PPRTV assessment should
be directed to the EPA Office of Research and Development's National Center for
Environmental Assessment, Superfund Health Risk Technical Support Center (513-569-7300).
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INTRODUCTION
2,2-Dichloropropane (2,2-DCP; synonyms: acetone dichloride; isopropylidene chloride;
dichlorodimethylmethane; dimethyldichloromethane) CAS No. 594-20-7, is a chloroalkane.
Chloroalkanes are used as industrial solvents, for degreasing of metals, as fumigants or
substitutes for terpenes, in dry cleaning, for soil sterilization, and as weed killers (Freitag et al..
1994). Based on its high vapor pressure, 2,2-DCP is volatile. A table of physicochemical
properties for 2,2-DCP is provided below (see Table 1). The molecular formula of 2,2-DCP is
C3H6C12 and the chemical structure is shown in Figure 1.
H3C
CI
CH,
CI
Figure 1. Structure of 2.2-DCP (NLM. 2011)
Table 1. Physicochemical Properties of 2,2-DCP (CASRN 594-20-7)3
Property (unit)
Value
Boiling point (°C)
69.3
Melting point (°C)
-35.0
Density (g/inL) (25°C)
1.082
Vapor pressure (atm at 25°C)
1.78 x 10"1
pH (unitless)
ND
Solubility in water (mg/L at 25°C)
391 (slightly soluble in water)
Relative vapor density (air = 1)
ND
Molecular weight (g/mol)
112.99
aChemIDplusLite (2011): U.S. EPA (2007): WolframMathematica (2011).
ND = no data.
No reference dose (RfD), reference concentration (RfC), or cancer assessment for
2,2,-DCP is included in the U.S. Environmental Protection Agency (EPA) Integrated Risk
Information System (IRIS) (U.S. EPA 2011b) or on the Drinking Water Standards and Health
Advisories List (U.S. EPA 2011a). No RfD or RfC values are reported in the Health Effects
Assessment Summary Tables (HEAST) (U.S. EPA 2003). The Chemical Assessments and
Related Activities (CARA) database does not include a Health and Environmental Effects Profile
(HEEP) for 2,2,-DCP (U.S. EPA 1994). The toxicity of 2,2,-DCP has not been reviewed by the
Agency for Toxic Substances and Disease Registry (ATSDR 2011) or the World Health
Organization (WHO. 2011). The California Environmental Protection Agency (Cal EPA. 2011.
2008) has not derived toxicity values for exposure to 2,2-DCP. No occupational exposure limits
for 2,2,-DCP have been derived or recommended by the American Conference of Governmental
Industrial Hygienists (ACGIH. 2011). the National Institute for Occupational Safety and Health
(NIOSH. 2007). or the Occupational Safety and Health Administration (OSHA. 2006).
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The HEAST (U.S. EPA. 2003) does not report any values. The International Agency for
Research on Cancer (IARC, 2011) has not reviewed the carcinogenic potential of 2,2,-DCP.
2,2,-DCP is not included in the 12th Report on Carcinogens (N I P. 2011). Cal EPA (2009) has
not prepared a quantitative estimate of the carcinogenic potential of 2,2,-DCP.
Literature searches were conducted on sources published from 1900 through May 2012
for studies relevant to the derivation of provisional toxicity values for 2,2-DCP, CAS No.
594-20-7. The following databases were searched by chemical name, synonyms, or CAS No.:
ACGM, ANEUPL, ATSDR, BIOSIS, Cal EPA, CCRIS, CDAT, ChemlDplus, CIS, CRISP,
DART, EMIC, EPIDEM, ETICBACK, FEDRIP, GENE-TOX, HAPAB, HERO, HMTC, HSDB,
IARC, INCHEM IPCS, IP A, ITER, IUCLID, LactMed, NIOSH, NTIS, NTP, OSHA, OPP/RED,
PESTAB, PPBIB, PPRTV, PubMed (toxicology subset), RISKLINE, RTECS, TOXLINE, TRI,
U.S. EPA IRIS, U.S. EPA HEAST, U.S. EPA HEEP, U.S. EPA OW, and U.S. EPA
TSCATS/TSCATS2. The following databases were searched for toxicity values or exposure
limits: ACGIH, ATSDR, Cal EPA, U.S. EPA IRIS, U.S. EPA HEAST, U.S. EPA HEEP,
U.S. EPA OW, U.S. EPA TSCATS/TSCATS2, NIOSH, NTP, OSHA, and RTECS.
REVIEW OF POTENTIALLY RELEVANT DATA
(CANCER AND NONCANCER)
No information is available regarding repeat-dose oral or inhalation exposure of humans
or animals to 2,2-DCP. An in vitro study by Tornero-Velez et al. (2004) investigated the
metabolism rates of 2,2-DCP and 1,3-DCP in rat liver microsomes and cytosol based on P450
and GST pathways in clearance and activation using gas chromatography. No metabolism of
2,2-DCP via a GSH-dependent conjugation pathway was observed, and the study authors
observed only a minor level of clearance via the P450 pathway (7 x 10 4L/h/mg microsomal
protein). 2,2-DCP was not mutagenic in various strains of Salmonella, including those
containing GSTT1-1, indicating that GSTT1-1 does not produce mutagenic metabolites
(Torne-Velez et al., 2004). Frietag et al. (1994) reported structural configurations and potential
influence on the toxicity of chloroalkanes including 2,2-DCP; however, the available data are
insufficient to perform a toxicity assessment of 2,2-DCP. Additionally, a preliminary
structure-activity relationship (SAR) analysis for this chemical did not suggest a reliable
surrogate chemical at this time.
DERIVATION OF PROVISIONAL VALUES
Limitations in the available data preclude development of both cancer and noncancer
toxicity values.
CANCER WEIGHT-OF-EVIDENCE (WOE) DESCRIPTOR
Limitations in the available data preclude development of a WOE descriptor.
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MODE-OF-ACTION (MOA) DISCUSSION
Limitations in the available data preclude determination of a MOA discussion.
REFERENCES
ACGIH (American Conference of Governmental Industrial Hygienists). (2011). 2011 TLVs and
BEIs: Based on the documentation of the threshold limit values for chemical substances
and physical agents and biological exposure indices. Cincinnati, OH.
http ://www. acgih.org/ store/ProductDetail. cfm?id=2147
ATSDR (Agency for Toxic Substances and Disease Registry). (2011). Toxicological profiles:
Information about contaminants found at hazardous waste sites. Available online at
http://www.atsdr.cdc.gov/toxprofiles/index.asp
Cal EPA (California Environmental Protection Agency). (2008). OEHHA acute, 8-hour and
chronic Reference Exposure Levels (chRELs) [Database], Retrieved from
http://www.oehha.ca.gov/air/allrels.html
Cal EPA (California Environmental Protection Agency). (2009). Appendix A: Hot spots unit risk
and cancer potency values. Sacramento, CA: Office of Environmental Health Hazard
Assessment, http://www.oehha.ca.gov/air/hot spots/2009/AppendixA.pdf
Cal EPA (California Environmental Protection Agency). (2011). OEHHA toxicity criteria
database. Sacramento, CA. http://www.oehha.ca. gov/tcdb/
Freitag, D; Ballhorn, L; Behechti, A; Fischer, K; Thumm, W. (1994). Structural configuration
and toxicity of chlorinated alkanes. Chemosphere 28: 253-259.
http://dx.doi.org/	3045-6535(94)90122-8
IARC (International Agency for Research on Cancer). (2011). IARC Monographs on the
evaluation of carcinogenic risk to humans. Available online at
http://monographs.iarc.fr/ENG/Monographs/PDFs/index.php
NIOSH (National Institute for Occupational Safety and Health). (2007). NIOSH pocket guide to
chemical hazards. (2005-149). Cincinnati, OH.
NLM (National Institutes of Health, National Library of Medicine). (2011). ChemlDplus Lite:
2,2-dichloropropane [Database], Bethesda, MD: National Library of Medicine. Retrieved
from http://chem.sis.nlm.nih.gov/chemidplus/chemidlite.isp
NTP (National Toxicology Program). (2011). Report on carcinogens: Twelfth edition.
Washington, DC: U.S. Department of Health and Human Services.
http://ntp.niehs.nih.gov/ntp/roc/twelfth/rocl2.pdf
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OSHA (Occupational Safety & Health Administration). (2006). Table Z-l limits for air
contaminants. Occupational Safety and Health Administration.
http://www.osha.gov/pls/oshaweb/owadisp.show docuinent?p table=STANDARDS&p
id=9992
Tornero-Velez, R; Ross, MK; Granville, C; Laskey, J; Jones, JP; Demarini, DM; Evans, MV.
(2004). Metabolism and mutagenicity of source water contaminants 1,3-dichloropropane
and 2,2-dichloropropane. Drug Metab Dispos 32: 123-131.
http://dx.doi.org/10.1124/dmd.32.L123
U.S. EPA (U.S. Environmental Protection Agency). (1994). Chemical assessments and related
activities (CARA) [EPA Report], (600R94904; OHEA-I-127). Washington, DC.
http://nepis.epa. gov/Exe/ZyPURL.cgi?Dockev=6000 lG8L.txt
U.S. EPA (U.S. Environmental Protection Agency). (2003). Health Effects Assessment
Summary Tables (HEAST). Available online at http://epa-h.east.oml.gov/
U.S. EPA (U.S. Environmental Protection Agency). (2007). Draft risk assessment for the
Siemens Water Technologies Corp. carbon reactivation facility, Parker, Arizona:
Appendix F: Chemical-physical parameters for compounds not included in USEPA's
HHRAP [EPA Report], San Francisco, CA.
http://www.epa.gov/region9/waste/siemens/pdf/RiskAssessment/siemens-
riskassessAppxF.pdf
U.S. EPA (U.S. Environmental Protection Agency). (201 la). 2011 Edition of the drinking water
standards and health advisories. (EPA 820-R-11-002). Washington, DC.
http://water.epa.gov/action/advisories/drinking/drinking index.cfm
U.S. EPA (U.S. Environmental Protection Agency). (2011b). Integrated Risk Information
System (IRIS). Available online at http://www.epa.gov/IRIS/
WHO (World Health Organization). (2011). Online catalog for the Environmental Health
Criteria Series. Available online at http://www.who.int/ipcs/publications/ehc/en/
Wolfram Mathematica (Wolfram Mathematica Documentation Center). (2011). 2,2-
dichloropropane [Fact Sheet], Champaign, IL: Wolfram Research Company.
http://www.wolframalpha.eom/entities/chemicals/2.2-dichloropropane/4i/bh/kc/
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