Californias Office of Environmental Health Hazard Assessment (OEHHA) is seeking public comments on a draft document describing proposed revised Reference Exposure Levels (RELs) for 1,3-butadiene. Reference Exposure Levels are concentrations in air that are not anticipated to result in adverse non-cancer health effects for specified exposure durations in the general population, including sensitive subpopulations. 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)). In response to this statutory requirement, OEHHA in 2008 adopted a Technical Support Document (TSD) that contains updated guidelines for the development of acute, 8 hour, and chronic RELs. These guidelines have already been used to develop updated RELs for several chemicals, and OEHHA is now presenting a draft update to the RELs for 1,3 butadiene. The values proposed are as follows: Acute REL (for a 1-hour exposure): 0.5 mg/m3 8-Hour REL (for repeated 8-hour exposures): 28 µg/m3 Chronic REL(for long-term exposures): 7 µg/m3 OEHHA are seeking comments on the revised RELs for 1,3-butadiene, and the application in the RELs document of the revised methodology to protect infants, children and other sensitive subpopulations. Following this public comment period, the RELs for 1,3-butadiene and any comments received, along with OEHHAs response to these comments, will undergo review by the States Scientific Review Panel on Toxic Air Contaminants. The draft documents are available at: draft documents. The public comment period will run for 60 days ending on 17 July 2012. Public workshops will be held during this period at which comments may be provided in person. One workshop will occur at 10:00 a.m. 3:00 p.m. on 9 July 2012 at: Room 10, Elihu Harris Building 1515 Clay St., 2nd Floor Oakland, CA 94612 A second public workshop will be held in Southern California: date, time and location will be announced shortly.
Californias OEHHA, 18 May 2012 ;http://www.oehha.ca.gov ;