IRIS

alpha-Hexachlorocyclohexane (alpha-HCH)

CASRN 319-84-6 | DTXSID2020684

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (10 pp, 104 K) Last Updated:
Not assessed under the IRIS Program.

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (10 pp, 104 K)
Not assessed under the IRIS Program.

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (10 pp, 104 K) Last Updated: 03/31/1987

WOE Characterization Framework for WOE Characterization
B2 (Probable human carcinogen - based on sufficient evidence of carcinogenicity in animals) Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986)
Basis:
  • Dietary alpha-HCH has been shown to cause increased incidence of liver tumors in five mouse strains and in Wistar rats.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (10 pp, 104 K)

Oral Slope Factor: 6.3 per mg/kg-day
Drinking Water Unit Risk: 1.8 x 10-4 per µg/L
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hepatic
Tumor type(s): Hepatic nodules and hepatocellular carcinomas (Ito et al., 1973a)


Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (10 pp, 104 K)

Inhalation Unit Risk: 1.8 x 10-3 per µg/m3
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hepatic
Tumor type(s): Hepatic nodules and hepatocellular carcinomas (Ito et al., 1973a)


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

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

Contact Us to ask a question, provide feedback or report a problem.