IRIS

Hexachlorocyclopentadiene (HCCPD)

CASRN 77-47-4

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (25 pp, 172 K) last updated: 07/05/2001

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Gastrointestinal 6 x 10-3 Chronic irritation BMDL10 : 6
mg/kg-day
1000 Low

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (25 pp, 172 K) last updated: 07/05/2001

System RfC (mg/m3) Basis PoD Composite UF Confidence
Respiratory 2 x 10-4 Suppurative inflammation of the nose NOAEL (HEC): 2.4 x 10-2
mg/m3
100 Medium

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (25 pp, 172 K) last updated: 07/05/2001

WOE Characterization Framework for WOE Characterization
E (Evidence of non-carcinogenicity for humans) Guidelines for Carcinogen Risk Assessment (US EPA, 1986)
Not likely to be carcinogenic to humans Proposed Guidelines for Carcinogen Risk Assessment (US EPA, 1996)
Basis:
  • According to the existing Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a), evaluation of the weight-of-evidence for carcinogenicity to humans indicates that HCCPD is most appropriately categorized as Group E, Evidence of Noncarcinogenicity to Humans, via inhalation exposure. In accordance with U.S. EPA's Proposed Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1996), HCCPD is not likely to be a human carcinogen by the inhalation route based on current data indicating no evidence of cancer in well-conducted bioassays in two species of rodents; the absence of increased deaths from cancer in the limited human occupational studies available; and lack of mutagenicity in a variety of test systems.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (25 pp, 172 K)

Not assessed under the IRIS Program.

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (25 pp, 172 K)

Not assessed under the IRIS Program.

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