Benzo[a]pyrene (BaP)

CASRN 50-32-8

Health Hazard Assessments for Effects Other than Cancer


Reference Dose for Oral Exposure (RfD) (PDF) (9 pp, 671 K) last updated: 01/19/2017

RfD (mg/kg-day) System Basis POD Composite UF Confidence
3 x 10-4 Developmental Neurobehavioral changes BMDL1SD(HED): 0.092 mg/kg-day 300 Medium

Reference Concentration for Inhalation Exposure (RfC) (PDF) (9 pp, 671 K) last updated: 01/19/2017

RfC (mg/m3) System Basis POD Composite UF Confidence
2 x 10-6 Developmental Decreased embryo/fetal survival LOAEL: 0.0046 mg/m3 3,000 Low/Medium

Cancer Assessment


Weight of Evidence for Cancer (PDF) (9 pp, 671 K) last updated: 01/19/2017

WOE Characterization Framework for WOE Characterization
Carcinogenic to humans Guidelines for Carcinogen Risk Assessment (US EPA, 2005)
Basis:
  • Under EPA’s Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005a), benzo[a]pyrene is “carcinogenic to humans” based on strong and consistent evidence in animals and humans.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (9 pp, 671 K)

Oral Slope Factor: 1 per mg/kg-day
Extrapolation Method: Time-to-tumor dose-response model with linear extrapolation from the POD (BMDL10HED) associated with 10% extra cancer risk.
Tumor site(s): Gastrointestinal
Tumor type(s): forestomach, esophagus, tongue, and larynx tumors (Kroese et al. 2001 Beland and Culp, 1998)


Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (9 pp, 671 K)

Inhalation Unit Risk: 6 x10 -4 per µg/m3
Extrapolation Method: Time-to-tumor dose-response model with linear extrapolation from the POD (BMCL10HED) associated with 10% extra cancer risk.
Tumor site(s): Gastrointestinal, Respiratory
Tumor type(s): Squamous cell neoplasia in the larynx, pharynx, trachea, nasal cavity, esophagus, and forestomach. (Thyssen et al., 1981)


Organ/System-Specific RfDs:

System Basis RfD (mg/kg-day) POD UF Confidence
Developmental Neurobehavioral changes 3 x 10-4 BMDL1SD(HED): 0.092 mg/kg-day 300 Medium
Reproductive Decreased ovarian follicles and ovary weight 4 x 10-4 BMDL1SD(HED): 0.37 mg/kg-day 1000 Medium
Immune Decreased thymus weight and serum IgM 2 x 10-3 BMDL1SD(HED): 1.9 mg/kg-day 1000 Low

Organ/System-Specific RfCs:

System Basis RfC (mg/m3) POD UF Confidence
Developmental Decreased embryo/fetal survival 2 x 10-6 LOAEL: 0.0046 mg/m3 3000 Low/Medium
Reproductive Reduced ovulation rate and ovary weight 3 x 10-6 LOAEL: 0.0091 mg/m3 3000 Low/Medium

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

Assessment Manager(s): Kathleen Newhouse (newhouse.kathleen@epa.gov)

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 01/2017

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

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