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alpha-Hexachlorocyclohexane (alpha-HCH) Quickview (CASRN 319-84-6)

Health assessment information on a chemical substance is included in IRIS only after a comprehensive review of toxicity data by U.S. EPA health scientists from several Program Offices, Regional Offices, and the Office of Research and Development.

Disclaimer: This QuickView represents a snapshot of key information. We suggest that you read the IRIS Summary to put this information into complete context.

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Status of Data for alpha-Hexachlorocyclohexane (alpha-HCH)

File First On-Line: 03/31/1987; Last Significant Revision: 03/31/1987

Category (section)
Last Revised
Oral RfD Assessment No
Inhalation RfC Assessment No
Carcinogenicity Assessment Yes 03/31/1987
  • 319-84-6
  • alpha-Benzenehexachloride
  • Benzene hexachloride-alpha-isomer
  • alpha-BHC
  • Cyclohexane, 1,2,3,4,5,6-hexachloro-, alpha-
  • Cyclohexane, 1,2,3,4,5,6-hexachloro-, alpha-isomer
  • ENT 9,232
  • alpha-HCH
  • alpha-Hexachloran
  • alpha-Hexachlorane
  • Hexachlorcyclohexan
  • more...
alpha-Hexachlorocyclohexane (alpha-HCH) Source Documents
Chronic Health Hazard Assessments for Noncarcinogenic Effects

Reference Dose for Chronic Oral Exposure (RfD)

Not Assessed under the IRIS Program.

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Reference Concentration for Chronic Inhalation Exposure (RfC)

Not Assessed under the IRIS Program.

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Carcinogenicity Assessment for Lifetime Exposure
  • Weight-of-Evidence Characterization
    • B2 (Probable human carcinogen - based on sufficient evidence of carcinogenicity in animals)
  • Weight-of-Evidence Narrative:
    • 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. See IRIS Summary.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure

Oral Slope Factor(s)
Extrapolation Method
6.3 per mg/kg-day Linearized multistage procedure, extra risk
Drinking Water Unit Risks
1.8x10-4 per µg/L
Risk Level
E-4 (1 in 10,000) 6x10-1 µg/L
E-5 (1 in 100,000) 6x10-2 µg/L
E-6 (1 in 1,000,000) 6x10-3 µg/L

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure

Inhalation Unit Risk(s)
Extrapolation Method
1.8 x10-3 per µg/m3 Linearized multistage procedure, extra risk

Inhalation Concentrations at Specified Risk Levels

Risk Level
E-4 (1 in 10,000) 6x10-2 µg/m3
E-5 (1 in 100,000) 6x10-3 µg/m3
E-6 (1 in 1,000,000) 6x10-4 µg/m3

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