Air Toxics Hot Spots Program Risk Assessment Guidelines Part III 1999

The Office of Environmental Health Hazard Assessment (OEHHA) is releasing a revised draft document, Air Toxics Hot Spots Program Risk Assessment Guidelines Part III: Technical Support Document for the Determination of Noncancer Chronic Reference Exposure Levels to solicit public comment on the revision and to obtain review by the ARB’s Scientific Review Panel. The original draft document was released in October 1997. More than forty sets of comments were received from the public. Staff have reviewed the comments, responded to the comments in writing, and revised the draft document.

This draft document is part of a series of Risk Assessment Guidelines that are being developed by OEHHA for use in implementing the Air Toxics "Hot Spots" Program mandated by the Air Toxics Hot Spots Information and Assessment Act of 1987, as amended. The revised draft document including the methodology (Introduction), toxicity summaries for the first 40 chemicals (based primarily on their emissions in California), and public comments with staff responses to the methodology and these 40 chemicals will be distributed for public review by June 11, 1999 . The distribution of the document will commence a 30-day public review period that will end on July 11, 1999.

Please direct any inquiries concerning technical matters or availability of the document to Dr. James Collins at (510) 622-3146. Please direct your written comments regarding the revised draft document to Dr. Melanie A. Marty, Chronic RELs, 1515 Clay St., 16th Floor, Oakland, CA 94612. Information about dates and agenda for meetings of the Scientific Review Panel can be obtained from the ARB web page at

The revised Draft Risk Assessment Guidelines document is available for download in 5 sections as Adobe Acrobat PDF files.  You must download all 5 sections to have the entire document.

Link to Public Comments

Response to Comments on the October 1997 Draft Air Toxics Hot Spots Program Risk Assessment Guidelines Part III