Proposed Revised Reference Exposure Levels for Caprolactam and Nickel
The Office of Environmental Health Hazard Assessment (OEHHA) is presenting draft documents for discussion by the Scientific Review Panel on Toxic Air Contaminants at its meeting on May 3, 2011 at the Milton Marks Conference Center, Earl Warren Building, San Francisco (see http://www.arb.ca.gov/srp/srpmeetings.htm for details and agenda). The documents comprise two separate items:
- Proposed Reference Exposure Levels (RELs) for caprolactam.
- Proposed Reference Exposure Levels (RELs) for nickel and nickel compounds.
OEHHA is required to develop guidelines for conducting health risk assessments under the Air Toxics Hot Spots Program [Health and Safety Code section 44360 (b) (2)]. OEHHA has developed Technical Support Documents (TSDs) in response to this statutory requirement, including the Technical Support Document for the Derivation of Noncancer Reference Exposure Levels, which was adopted in December 2008 and the Technical Support Document for Cancer Potency Factors, which was adopted in June 2009.
A previous version of the document describing the proposed for Caprolactam was discussed by the SRP at the previous meeting on January 21, 2011. A revised version incorporating revisions to address the SRP’s comments is now presented for further consideration by the panel. Proposed values for the 8 hour, and chronic RELs are 7 µg/m3 (1 ppb), and 2 µg/m3 (0.5 ppb), respectively; a value for the acute REL is not now being proposed. These were developed using the latest version of the non-cancer REL guidelines, including application of the revised methodology to protect infants, children and other sensitive subpopulations. When finalized and adopted, these RELs will be added to the compound-specific toxicity reviews and summary tables which appear as appendices to the Technical Support Document for the Derivation of Noncancer Reference Exposure Levels.
An earlier draft of the document describing the nickel RELs was presented on June 4, 2010 for public comment, and OEHHA has reviewed the comments received and prepared responses, as well as revising the REL document where appropriate. The nickel REL document, along with the public comments and OEHHA’s response to these comments, will now undergo review by the State’s Scientific Review Panel on Toxic Air Contaminants (Health and Safety Code section 39670 et seq.).
Please direct any inquiries concerning technical matters, availability of documents or comparison between these and previous versions to John Budroe at (510) 622-3145 or John.Budroe@oehha.ca.gov