Workshop: Air Toxics Hot Spots Draft Guidance Manual
The Office of Environmental Health Hazard Assessment (OEHHA) today released a draft guidance manual designed to improve the way the State estimates potential lifetime health risks from toxic air contaminants. The release triggers a 45-day public comment period.
The draft OEHHA Guidance Manual makes adjustments based on new science about both increased childhood exposure to and sensitivity to air toxics. Over the past 10 years, scientific advances have shown that early-life exposures to air toxics contribute to an increased lifetime risk of developing cancer and other adverse health effects, compared to exposures that occur in adulthood.
A 1999 state law, SB 25 by Sen. Martha Escutia, requires that the special susceptibility of infants and children be considered in assessing the health risks associated with air toxics. The U.S. Environmental Protection Agency also takes into account the increased susceptibility of infants and children to toxic chemicals.
The draft guidance manual summarizes three Technical Support Documents focused on non-cancer risk, cancer risk, and exposure assessment, respectively. The guidance manual weaves together the information in all three documents and provides a method for using the information to estimate health risks from air pollution sources as called for under the Air Toxics Hot Spots Information and Assessment Act.
The three technical documents underwent public and peer review and were finalized in 2008, 2009 and 2012.
The methodologies contained in the draft manual seek to develop more accurate estimates of the risks from emissions of air toxics. Measurements of air toxics indicate exposures and health risks have declined significantly over the past 25 years. The new methodologies would result in higher estimated risks for many situations than would have been calculated by the existing risk methodology. In some cases, the new estimated cancer risk would be only slightly higher than the current estimate; in other cases, the new estimated cancer risk could be up to three times higher.
The new draft guidance document is part of California’s ongoing effort to address health risks from toxics in the air. Data from the statewide air toxics monitoring network of the Air Resources Board (ARB) shows there has been a reduction in cancer risk of more than 80 percent since 1990.Emission reductions from technological controls and other measures required by state and local regulations occurred even while the population and number of vehicles in California both doubled.
The online posting of the draft Guidance Manual starts a 45-day public review period that will end on August 4. In addition, there will be two public workshops in July.
OEHHA is seeking comments primarily on the utility of the draft manual for conducting a risk assessment. As noted above, the underlying scientific information that originally appeared in the three Technical Support Documents has already undergone public and peer review, approval by the Scientific Review Panel on Toxic Air Contaminants (SRP), and adoption by OEHHA.
After OEHHA reviews the public comments and makes appropriate changes, the draft Guidance Manual will be reviewed by the SRP. After approval by the SRP and the Director of OEHHA, the Guidance Manual will be adopted for use by the ARB and local air districts in the Air Toxics Hot Spots program.
Public workshops will be held at the following locations and times:
July 15, 2014, 1:00 to 5:00 pm
CC-2
South Coast Air Quality Management District
21865 E. Copley Drive,
Diamond Bar, CA 91765