Heptachlor epoxide

CASRN 1024-57-3

  • IRIS Summary (PDF) (14 pp, 121 K)
  • Status: Heptachlor epoxide is not being reassessed by IRIS at this time.

Health Hazard Assessments for Effects Other than Cancer


Reference Dose for Oral Exposure (RfD) (PDF) (14 pp, 121 K) last updated: 09/30/1987

RfD (mg/kg-day) System Basis PoD Composite UF Confidence
1.3 x10-5 Hepatic Increased liver-to-body weight ratio in both males and females LEL : 1.25 x10-2
mg/kg-day
1000 Low

Reference Concentration for Inhalation Exposure (RfC) (PDF) (14 pp, 121 K)
Not assessed under the IRIS Program.

Cancer Assessment


Weight of Evidence for Cancer (PDF) (14 pp, 121 K) last updated: 09/30/1987

WOE Characterization Framework for WOE Characterization
B2 (Probable human carcinogen - based on sufficient evidence of carcinogenicity in animals) Guidelines for Carcinogen Risk Assessment (US EPA, 1986)
Basis:
  • Sufficient evidence exists from rodent studies in which liver carcinomas were induced in two strains of mice of both sexes and in CFN female rats. Several structurally related compounds are liver carcinogens.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (14 pp, 121 K)

Oral Slope Factor: 9.1 per mg/kg-day
Drinking Water Unit Risk: 2.6 x10 -4 per µg/L
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hepatic
Tumor type(s): Hepatocellular carcinomas (Davis, 1965; Velsicol, 1973)


Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (14 pp, 121 K)

Inhalation Unit Risk: 2.6 x10 -3 per µg/m3
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hepatic
Tumor type(s): Hepatocellular carcinomas (Davis, 1965; Velsicol, 1973)


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