IRIS

Chloroprene

CASRN 126-99-8

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (30 pp, 307 K) last updated: 09/30/2010
Information reviewed but value not estimated.

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (30 pp, 307 K) last updated: 09/30/2010

System RfC (mg/m3) Basis PoD Composite UF Confidence
Nervous, Immune, Respiratory 2 x 10-2 Increase in incidence of olfactory atrophy, alveolar hyperplasia, and splenic hematopoietic proliferation in male F344/N rats, female F344/N rats, and female B6C3F1 mice, respectively BMDL (HEC): 2
mg/m3
100 Medium/High
Nervous, Immune, Respiratory 2 x 10-2 Increase in incidence of olfactory atrophy, alveolar hyperplasia, and splenic hematopoietic proliferation in male F344/N rats, female F344/N rats, and female B6C3F1 mice, respectively BMDL (HEC): 2
mg/m3
100 Medium/High
Nervous, Immune, Respiratory 2 x 10-2 Increase in incidence of olfactory atrophy, alveolar hyperplasia, and splenic hematopoietic proliferation in male F344/N rats, female F344/N rats, and female B6C3F1 mice, respectively BMDL (HEC): 2
mg/m3
100 Medium/High

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (30 pp, 307 K) last updated: 09/30/2010

WOE Characterization Framework for WOE Characterization
Likely to be carcinogenic to humans Guidelines for Carcinogen Risk Assessment (US EPA, 2005)
Basis:
  • Under the Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005), there is evidence that chloroprene is "likely to be carcinogenic to humans"
  • This may be a synopsis of the full weight-of-evidence narrative.

WOE Footnote:  EPA has concluded, by a weight of evidence evaluation, that chloroprene is carcinogenic by a mutagenic mode of action. Age-dependent adjustment factors (ADAFs) should be used when estimating age-specific cancer risks. See IRIS Summary.


Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (30 pp, 307 K)

Information reviewed but value not estimated.


Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (30 pp, 307 K)

Inhalation Unit Risk: 3 x10 -4 per µg/m3
Extrapolation Method: Multistage model with linear extrapolation from the point of departure (BMDL), summed risk.
Tumor site(s): Reproductive, Ocular, Other, Hepatic, Gastrointestinal, Respiratory, Dermal
Tumor type(s): alveolar/ bronchiolar adenoma or carcinoma hemangioma/ hemangiosarcoma (all organs) mammary gland adenocarcinoma, carcinoma, or adenoacanthoma forestomach squamous cell papilloma or carcinoma hepatocellular adenoma or carcinoma Harderian gland adenoma or carcinoma skin sarcoma and Zymbal's gland carcinoma (NTP, 1998)


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