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Benzene

CASRN 71-43-2 | DTXSID3039242

  • Toxicological Review (PDF) (180 pp, 1.59 M)
  • IRIS Summary (PDF) (45 pp, 261 K)
  • Supporting Documents for Benzene (Cancer)

On this page:

  • Key IRIS
    Values
  • Chemical
    Documents
  • Other EPA
    Information

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (45 pp, 261 K) Last Updated: 04/17/2003

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Immune 4 x 10 -3 Decreased lymphocyte count BMDL : 1.2
mg/kg-day
300 Medium

Reference Concentration for Inhalation Exposure (RfC) (PDF) (45 pp, 261 K) Last Updated: 04/17/2003

System RfC (mg/m3) Basis PoD Composite UF Confidence
Immune 3 x 10 -2 Decreased lymphocyte count BMCL : 8.2
mg/m3
300 Medium

Cancer Assessment

Weight of Evidence for Cancer (PDF) (45 pp, 261 K) Last Updated: 01/09/2000

WOE Characterization Framework for WOE Characterization
A (Human carcinogen) Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986)
Known/likely human carcinogen Proposed Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1996)
Basis:
  • Benzene is classified as a "known" human carcinogen (Category A) under the Risk Assessment Guidelines of 1986. Under the proposed revised Carcinogen Risk Assessment Guidelines (U.S. EPA, 1996), benzene is characterized as a known human carcinogen for all routes of exposure based upon convincing human evidence as well as supporting evidence from animal studies. (U.S. EPA, 1979, 1985, 1998; ATSDR, 1997).
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (45 pp, 261 K)

Oral Slope Factor: 1.5 x 10-2 per mg/kg-day
Drinking Water Unit Risk: 4.4 x 10-7 per µg/L
Extrapolation Method: Linear extrapolation of human occupational data
Tumor site(s): Hematologic
Tumor type(s): Leukemia (Rinsky et al., 1981, 1987 Paustenbach et al., 1993 Crump, 1994 U. S. EPA, 1998 U.S. EPA, 1999)

Oral Slope Factor: 5.5 x 10-2 per mg/kg-day
Drinking Water Unit Risk: 1.6 x 10-6 per µg/L
Extrapolation Method: Linear extrapolation of human occupational data
Tumor site(s): Hematologic
Tumor type(s): Leukemia (Rinsky et al., 1981, 1987 Paustenbach et al., 1993 Crump, 1994 U. S. EPA, 1998 U.S. EPA, 1999)


Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (45 pp, 261 K)

Inhalation Unit Risk: 2.2 x 10-6 per µg/m3
Extrapolation Method: Low-dose linearity utilizing maximum likelihood estimates
Tumor site(s): Hematologic
Tumor type(s): Leukemia (Rinsky et al., 1981, 1987 Paustenbach et al., 1993 Crump and Allen, 1984 Crump, 1992, 1994 U.S. EPA, 1998)

Inhalation Unit Risk: 7.8 x 10-6 per µg/m3
Extrapolation Method: Low-dose linearity utilizing maximum likelihood estimates
Tumor site(s): Hematologic
Tumor type(s): Leukemia (Rinsky et al., 1981, 1987 Paustenbach et al., 1993 Crump and Allen, 1984 Crump, 1992, 1994 U.S. EPA, 1998)

Chemical Documents

Jun 2002: IRIS Toxicological Review of Benzene (Noncancer Effects) (Report)

May 1999: EXTRAPOLATION OF THE BENZENE INHALATION UNIT RISK ESTIMATE TO THE ORAL ROUTE OF EXPOSURE (EXTERNAL REVIEW DRAFT) (Report)

Sep 1998: IRIS Toxicological Review of Benzene (Noncancer Effects) (1998 External Review Draft) (Report)

Jun 1997: Carcinogenic Effects of Benzene: An Update (1997 External Review Draft) (Report)

Sep 1984: HEALTH EFFECTS ASSESSMENT FOR BENZENE (Report)

Other EPA Information

Additional EPA toxicity information may be available by visiting the following sites:
  • Human Health Benchmarks for Pesticides (HHBP). This database provides human health benchmarks for pesticides that may be present in drinking water.
  • Office of Pesticide Programs Pesticide Chemical Search. This database provides links to health effects information and registration status for pesticides.
  • Chemistry Dashboard. This database provides information on chemical structures, experimental and predicted physicochemical, and toxicity data.

Related Links

  • EPA Chemicals Dashboard - Benzene
  • eChemPortal - Benzene

Critical Effects

Immune
Immune

Tumor Sites

Hematologic
Hematologic

Chemical Structure

Benzene

Synonyms

  • Benzene
  • Benzol
  • Coal naphtha
  • Cyclohexatriene
  • Phene
  • Phenyl hydride
  • Polystream
  • Pyrobenzol
  • 71-43-2
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