Notice for Public Comment on Draft Air Toxics Hot Spots Program Risk Assessment Guidelines Part III 22 Chronic RELs (2nd Set) Sept 1999

The Office of Environmental Health Hazard Assessment (OEHHA) is releasing the second part of 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. 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 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.

The original 1997 document contained a description of the methodology and toxicity summaries and Reference Exposure Levels for 120 compounds. To facilitate review, OEHHA decided to release the chemical toxicity summaries in batches of 40. In June 1999 a 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 were distributed for review. This notice pertains to the toxicity summaries for the second set of 40 chemicals, which will be distributed for public review (along with the responses to comments received during the first public comment period) by September 27, 1999. The document is available in the download area below. The distribution of the document will commence a 30-day public review period that will end on October 27, 1999. We are soliciting public input on the second batch of toxicity summaries and Reference Exposure Levels during this public comment period.

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

Link to Public Comments

Response to Comments on the October 1997 Draft of the Air Toxics Hot Spots Risk Assessment Guidelines Part III 22 RELs 2nd Set

Monday, September 27, 1999