IRIS

Hexachlorobutadiene

CASRN 87-68-3

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (9 pp, 100 K) last updated: 05/01/1993
Information reviewed but value not estimated.

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (9 pp, 100 K)
Not assessed under the IRIS Program.

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (9 pp, 100 K) last updated: 03/31/1987

WOE Characterization Framework for WOE Characterization
C (Possible human carcinogen) Guidelines for Carcinogen Risk Assessment (US EPA, 1986)
Basis:
  • Observation of renal neoplasms in male and female rats in one study.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (9 pp, 100 K)

Oral Slope Factor: 7.8 x10 -2 per mg/kg-day
Drinking Water Unit Risk: 2.2 x10 -6 per µg/L
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Urinary
Tumor type(s): Renal tubular adenomas and adenocarcinomas (Kociba et al., 1977)



Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (9 pp, 100 K)

Inhalation Unit Risk: 2.2 x10 -5 per µg/m3
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Urinary
Tumor type(s): Renal tubular adenomas and adenocarcinomas (Kociba et al., 1977)


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