Benzo[a]pyrene (BaP)

CASRN 50-32-8

Health Hazard Assessments for Effects Other than Cancer

Reference Dose for Oral Exposure (RfD) (PDF) (15 pp, 124 K)
Not assessed under the IRIS Program.

Reference Concentration for Inhalation Exposure (RfC) (PDF) (15 pp, 124 K)
Not assessed under the IRIS Program.

Cancer Assessment

Weight of Evidence for Cancer (PDF) (15 pp, 124 K) last updated: 11/01/1994

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)
  • Human data specifically linking benzo[a]pyrene (BAP) to a carcinogenic effect are lacking. There are, however, multiple animal studies in many species demonstrating BAP to be carcinogenic following administration by numerous routes. BAP has produced positive results in numerous genotoxicity assays.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (15 pp, 124 K)

Oral Slope Factor: 7.3 per mg/kg-day
Drinking Water Unit Risk: 2.1 x10 -4 per µg/L
Extrapolation Method: Risk estimate based on a geometric mean of four slope factors obtained by different modeling procedures
Tumor site(s): Gastrointestinal
Tumor type(s): Forestomach, squamous cell papillomas and carcinomas; forestomach, larynx and esophagus, papillomas and carcinomas (combined) (Neal and Rigdon, 1967; Rabstein et al., 1973; Brune et al., 1981)

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (15 pp, 124 K)

Not Assessed under the IRIS Program.

Benzo[a]pyrene (BaP) is being reassessed.

Assessment Manager(s): Kathleen Newhouse (

Step Assessment Materials Released to the Public Release Date Public Meeting Date
1 Problem Formulation Materials N/A N/A
1 Preliminary Assessment Materials N/A N/A
4 Public Comment Draft 08/2013 12/2013
4 Peer Review Draft 09/2014 04/2015
7 Post Final Assessment TBD

Please note: Any future dates displayed under Release Date are estimates and subject to change.

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