Meeting of the Scientific Review Panel for Toxic Air Contaminants on January 21, 2011
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 at 9:00 a.m. on January 21, 2011 at the University of California, Berkeley (Room 150, University Hall, 2199 Addison Street, Berkeley, California 94720: see http://www.arb.ca.gov/srp/srpmeetings.htm for details and agenda). The documents comprise two separate items:
- Use of the Toxicity Equivalency Factor (TEFWHO‑97 and TEFWHO‑05) Scheme for Estimating Toxicity of Mixtures of Dioxin-Like Chemicals.
- A document describing proposed Reference Exposure Levels (RELs) for caprolactam. See ERRATA January 6, 2011 (below)
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.
The document presented here on Toxicity Equivalence Factors for dioxin-like compounds is a proposed revision to the previous version that appears as Appendix C of the Technical Support Document for Cancer Potency Factors.
ERRATA for RELs for Caprolactam
On 12/27/10, it was stated in this summary that the proposed acute, 8-hour, and chronic RELs for Caprolactam, were 770 µg/m3 (170 ppb), 10 µg/m3 (2 ppb), and 4 µg/m3 (0.8 ppb), respectively. The correct acute, 8-hour and chronic values are 770 µg/m3 (170 ppb), 7 µg/m3 (1 ppb), and 2 µg/m3 (0.5 ppb), respectively. This error also appeared in the document describing the Proposed Reference Exposure Levels for Caprolactam, Summary Section 1.2 and 1.3, page 2. The correct values appeared elsewhere in the document. OEHHA posted a corrected version of the Document Describing Proposed Reference Exposure Levels for Caprolactam on 01/06/11. OEHHA regrets the error.
The REL values 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.
Earlier drafts of these documents have already been presented for public comment, and OEHHA has reviewed the comments received and prepared responses, as well as revising the documents where appropriate. These documents, 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.).
- Adoption of Revised Toxicity Equivalency Factors for TEF(WHO-05) for PCDDs, PCDFs, and Dioxin-like PCBsJan 31, 2011Notice of Public Comment for Revisions to TSD for Cancer Potency Factors Appendix C - Use of Toxicity Equivalence Factors Scheme for Estimating Toxicity of Mixtures of Dioxin-like ChemicalsAug 7, 2009