Trichloropropane CASRN 96-18-4 | IRIS

IRIS

1,2,3-Trichloropropane

CASRN 96-18-4 | DTXSID9021390

Toxicological Review (PDF) (247 pp, 1.91 M)
IRIS Summary (PDF) (33 pp, 283 K)

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (33 pp, 283 K) Last Updated: 09/30/2009

System	RfD (mg/kg-day)	Basis	PoD	Composite UF	Confidence
Hepatic	4 x 10 ^-3	Increased absolute liver weight in male rats	BMDL (ADJ): 1.1 mg/kg-day	300	Medium/High

Reference Concentration for Inhalation Exposure (RfC) (PDF) (33 pp, 283 K) Last Updated: 09/30/2009

System	RfC (mg/m³)	Basis	PoD	Composite UF	Confidence
Respiratory	3 x 10 ^-4	peribronchial lymphoid hyperplasia in male rats	BMCL (HEC): 0.90 mg/m³	3000	Low

Cancer Assessment

Weight of Evidence for Cancer (PDF) (33 pp, 283 K) Last Updated: 09/30/2009

WOE Characterization	Framework for WOE Characterization
Likely to be carcinogenic to humans	Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005)

Basis:

Under the Guidelines for Carcinogenic Risk Assessment (U.S. EPA, 2005), 1,2,3-trichloropropane is "likely to be carcinogenic to humans", based on a statistically significant and dose-related increase in the formation of multiple tumors in both sexes of two species from an NTP (1993) chronic oral bioassay.
This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (33 pp, 283 K)

Oral Slope Factor: 5 x 10^-1 per mg/kg-day
Extrapolation Method: Multistage-Weibull model with linear extrapolation from the point of departure (BMDL₁₀), includes application of age-dependent adjustment factors (ADAFs).
Tumor site(s): Hepatic, Gastrointestinal, Ocular, Reproductive
Tumor type(s): alimentary system squamous cell neoplasms, liver hepatocellular adenomas or carcinomas, Harderian gland adenomas, uterine/cervix adenomas or carcinomas (NTP, 1993)
Note: EPA has concluded that 1,2,3-trichloropropan is carcinogenic by a mutagenic mode of action. Thus, based on the EPA cancer guidelines (2005), the oral slope factor (OSF) addressing lifetime exposure includes application of ADAFs. The OSF is recommended for lifetime exposures. EPA has also provided an adult-based cancer slope factor of 3 x 10¹ per mg/kg-day. This adult-based cancer slope factor can be used instead of the OSF when assessing cancer risk associated with exposure scenarios that don’t include early life (< 16 years of age) or when other calculations by the user are necessary (e.g., when applying ADAFs to age-specific exposure estimates).

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (33 pp, 283 K)

Not Assessed under the IRIS Program.

Oct 2009: IRIS Toxicological Review of 1,2,3-trichloropropane (Interagency Science Discussion Draft) (Report)

Sep 2009: IRIS Toxicological Review and Summary Documents For 1,2,3-Trichloropropane (Report)

Nov 2007: IRIS Toxicological Review of 1,2,3-Trichloropropane (External Review Draft) (Report)

Additional EPA toxicity information may be available by visiting the following sites:

Human Health Benchmarks for Pesticides (HHBP). This database provides human health benchmarks for pesticides that may be present in drinking water.
Office of Pesticide Programs Pesticide Chemical Search. This database provides links to health effects information and registration status for pesticides.
Chemistry Dashboard. This database provides information on chemical structures, experimental and predicted physicochemical, and toxicity data.

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