IRIS Toxicological Review of Benzo[a]pyrene (Interagency Science Consultation Draft)

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On August 21, 2013, the draft Toxicological Review of Benzo[a]pyrene and the draft charge to external peer reviewers were released for public review and comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House Offices before public release. Consistent with the May 2009 IRIS assessment development process, all written comments on IRIS assessments submitted by other federal agencies and White House Offices are made publicly available. Accordingly, interagency comments and the interagency science consultation materials provided to other agencies, including interagency review drafts of the IRIS Toxicological Review of Benzo[a]pyrene and the charge to external peer reviewers, are posted on this site.

BaP is found in the environment primarily as a result of the incomplete burning of materials that contain carbon. It is one of a group of compounds called polycyclic aromatic hydrocarbons (PAHs). BaP (along with other PAHs) is released into the atmosphere as a component of smoke from forest fires, industrial processes, vehicle exhaust, cigarettes, and through the burning of fuel (such as wood, coal, and petroleum products). People can be exposed to BaP by breathing particles that contain carbon (e.g. soot, diesel particles) to which PAHs have adhered. People can also be exposed to BaP by eating foods grown in areas with air or soil contaminated with BaP or by eating certain food products, such as charred meats, where BaP is formed during the cooking process. People can also be exposed to BaP through the skin after coming into contact with soils or materials that contain soot, tar, or crude petroleum products or by using certain pharmaceutical products containing coal tars, such as those used to treat the skin conditions eczema and psoriasis.

This draft is a reassessment of an IRIS assessment posted in 1987 and includes an oral reference dose, inhalation reference concentration, oral slope factor, inhalation unit risk, and dermal slope factor. It is the first IRIS assessment to propose a dermal slope factor.


EPA is undertaking an update of the Integrated Risk Information System (IRIS) health assessment for benzo[a]pyrene (BaP). The outcome of this project is an updated Toxicological Review and IRIS Summary for BaP that will be entered into the IRIS database.


Following public comment and external peer review, the assessment will be revised taking into consideration peer review and public comments. The assessment will then undergo a final EPA internal review and a review by and science discussion with other federal agencies and White House offices. Once final, the assessment will be posted to the IRIS database.


U.S. EPA. IRIS Toxicological Review of Benzo[a]pyrene (Interagency Science Consultation Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-10/006, 2013.


Date Description
01-Jun 2011EPA initiated the interagency science consultation on the draft Toxicological Review of Benzo[a]pyrene.
02-Aug 2013EPA released the external review draft for public review and comment.

This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.