As previously reported, the Office of Environmental Health Hazard Assessment (OEHHA) adopted the revised Air Toxics Hot Spots Program Guidance Manual for Preparation of Health Risk Assessments in February 2015. Referred to as the OEHHA Manual, the final version can be found here. It was developed by OEHHA, in conjunction with the California Air Resources Board (ARB) for use with local air district stationary source permitting and the Air Toxics Hot Spots programs (AB2588). ARB has also released an updated version of the Hot Spots Analysis and Reporting Program (HARP 2) in support of the OEHHA Manual. The HARP software update is available for download here. The OEHHA Manual and HARP 2 incorporate children's health concerns and risk assessment methodology, triggered by the Children's Health Protection Act of 1999 (SB 25, Stats. 1999). These updates also provide consistent health risk assessment (HRA) procedures.

The revised OEHHA Manual directly affects California air district health risk programs including stationary source permitting (Risk Management Review), CEQA, and AB2588. According to the Bay Area Air Quality Management District (BAAQMD), the new guidance could result in 2 to 5 fold increases in predicted cancer risk for the same emission levels. According to ARB, there might be a 1.5 to 3 fold increase in predicted cancer risk with inhalation-only assessments, and additional increases in potential cancer risk estimates with multiple pathways of exposure. With either prediction level, air districts risk-related work load would increase. The BAAQMD estimated 150 new permit applications per year requiring HRAs and 750 existing facilities triggering further prioritization analysis. These BAAQMD findings suggest work load impacts on all California air districts from air permits, AB2588 facility compliance and CEQA projects that might not have previously triggered an HRA threshold.

The San Joaquin Valley Air Pollution Control District (SJVAPCD) has recently revised its health risk thresholds for air permits and CEQA projects from 10 in a million to 20 in a million for cancer risk; its AB2588 thresholds remain at 10 in a million for cancer risk. The SJVAPCD also implemented a tiered approach to its risk assessments. More information about the recent SJVAPCD rule revision can be found here. Other air districts may also consider rule or policy revisions.

ARB just published new Risk Management Guidance for Stationary Sources of Air Toxics, a discussion draft (May 27, 2015), and can be found here. This guidance focuses on communication challenges from anticipated higher predicted cancer risk levels. Many existing facilities that are not proposing any changes in operations, are already using control technology and are actually maintaining or reducing their emissions. However, under the methodology provided in the revised OEHHA Manual, they will be reporting substantially higher cancer risk levels and may now require risk management plans. The challenge will be in ensuring the public's right to know while communicating that revised public health impacts do not necessarily correspond to increases in emissions or operational changes at facilities.