Hexachlorodibenzo-p-dioxin (HxCDD), mixture of 1,2,3,6,7,8-HxCDD and 1,2,3,7,8,9-HxCDD

CASRN 57653-85-7, 19408-74-3

  • IRIS Summary (PDF) (10 pp, 102 K)
  • Status: Hexachlorodibenzo-p-dioxin (HxCDD), mixture of 1,2,3,6,7,8-HxCDD and 1,2,3,7,8,9-HxCDD is not being reassessed by IRIS at this time.

Health Hazard Assessments for Effects Other than Cancer


Reference Dose for Oral Exposure (RfD) (PDF) (10 pp, 102 K)
Not assessed under the IRIS Program.

Reference Concentration for Inhalation Exposure (RfC) (PDF) (10 pp, 102 K)
Not assessed under the IRIS Program.

Cancer Assessment


Weight of Evidence for Cancer (PDF) (10 pp, 102 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 (US EPA, 1986)
Basis:
  • Hepatic tumors in mice and rats by gavage
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (10 pp, 102 K)

Oral Slope Factor: 6.2 x10 3 per mg/kg-day
Drinking Water Unit Risk: 1.8 x10 -1 per µg/L
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hepatic
Tumor type(s): Liver tumors (adenomas and carcinomas; neoplastic nodules and hepatocellular carcinomas) (NTP, 1980a)


Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (10 pp, 102 K)

Inhalation Unit Risk: 1.3 per µg/m3
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hepatic
Tumor type(s): Liver tumors (adenomas and carcinomas; neoplastic nodules and hepatocellular carcinomas) (NTP, 1980a)


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