IRIS

technical Hexachlorocyclohexane (t-HCH)

CASRN 608-73-1 | DTXSID7020687

  • IRIS Summary (PDF) (9 pp, 101 K)
  • Status: EPA announced in a 2004 Federal Register Notice that chemicals used as pesticides would not be re-assessed by the IRIS Program. This entry in the IRIS database is preserved at the request of EPA program and regional offices. Additional toxicological information may be found under "Other EPA Information."

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (9 pp, 101 K) Last Updated:
Not assessed under the IRIS Program.

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (9 pp, 101 K)
Not assessed under the IRIS Program.

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (9 pp, 101 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:
  • Assays in four strains of mice have yielded positive carcinogenicity results for t-HCH administered in the diet.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (9 pp, 101 K)

Oral Slope Factor: 1.8 per mg/kg-day
Drinking Water Unit Risk: 5.1 x 10-5 per µg/L
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hepatic
Tumor type(s): Liver nodules and hepatocellular carcinomas (Munir et al., 1983)


Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (9 pp, 101 K)

Inhalation Unit Risk: 5.1 x 10-4 per µg/m3
Extrapolation Method: Linearized multistage procedure
Tumor site(s): Hepatic
Tumor type(s): Liver nodules and hepatocellular carcinomas (Munir et al., 1983)


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

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