1,2-Dibromoethane

CASRN 106-93-4

Toxicological Review (PDF) (240 pp, 3.73 M)
IRIS Summary (PDF) (34 pp, 241 K)
Status: 1,2-Dibromoethane is not being reassessed by IRIS at this time.

Key IRIS Values

Health Hazard Assessments for Effects Other than Cancer

Reference Dose for Oral Exposure (RfD) (PDF) (34 pp, 241 K) last updated: 07/29/2004

RfD (mg/kg-day)	System	Basis	PoD	Composite UF	Confidence
9 x10^-3	Endocrine, Reproductive, Hepatic	Testicular atrophy, liver peliosis, and adrenal cortical degeneration	LOAEL : 27 mg/kg-day	3000	Low/Medium

Reference Concentration for Inhalation Exposure (RfC) (PDF) (34 pp, 241 K) last updated: 07/29/2004

RfC (mg/m³)	System	Basis	PoD	Composite UF	Confidence
9 x10^-3	Respiratory	Nasal inflammation	BMCL₁₀ (HEC): 2.8 mg/m³	300	Medium

Cancer Assessment

Weight of Evidence for Cancer (PDF) (34 pp, 241 K) last updated: 07/29/2004

WOE Characterization	Framework for WOE Characterization
Likely to be carcinogenic to humans	Revised Draft Guidelines for Carcinogen Risk Assessment (US EPA, 1999)

Basis:

Under the Draft Revised Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1999), 2-dibromoethane is considered "likely to be carcinogenic to humans" based on strong evidence of carcinogenicity in animals and inconclusive evidence of carcinogenicity in an exposed human population.
This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (34 pp, 241 K)

Oral Slope Factor: 2 per mg/kg-day (95% upper bound)
Drinking Water Unit Risk: 6 x10^-5 per µg/L (95% upper bound)
Extrapolation Method: Multistage model with Poly-3 adjusted incidence data linear extrapolation from lower 95% confidence limit on dose associated with extra risk (adjusted for background) at point of departure at lower end of data range.
Tumor site(s): Other, Gastrointestinal, Endocrine
Tumor type(s): Forestomach tumors, hemangiosarcomas, thyroid follicular cell adenomas or carcinomas (NCI, 1978)

Oral Slope Factor: 1 mg/kg-day (central tendency estimate)
Extrapolation Method: Multistage model with Poly-3 adjusted incidence data central tendency estimate
Tumor site(s): Other, Gastrointestinal, Endocrine
Tumor type(s): Forestomach tumors, hemangiosarcomas, thyroid follicular cell adenomas or carcinomas (NCI, 1978)

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (34 pp, 241 K)

Inhalation Unit Risk: 6 x10^-4 per µg/m³ (95% upper bound)
Extrapolation Method: Multistage-Weibull model linear extrapolation from lower 95% confidence limit on dose associated with extra risk (adjusted for background) at point of departure at lower end of data range.
Tumor site(s): Reproductive, Other, Respiratory
Tumor type(s): Nasal cavity (includes adenoma, adenocarcinoma, papillary adenoma, squamous cell carcinoma, and or/papilloma), hemangiosarcomas, mesotheliomas (NTP, 1982)

Inhalation Unit Risk: 3 x10^-4 per µg/m³ (central tendency estimate)
Extrapolation Method: Multistage model with Poly-3 adjusted incidence data central tendency estimate
Tumor site(s): Reproductive, Other, Respiratory
Tumor type(s): Nasal cavity (includes adenoma, adenocarcinoma, papillary adenoma, squamous cell carcinoma, and or/papilloma), hemangiosarcomas, mesotheliomas (NTP, 1982)