The Bay Area Air Quality Management District (BAAQMD) is proposing revisions to the Regulation 2, Rule 5, New Source Review of Toxic Air Contaminants (Rule 2-5).  Rule 2-5 implements BAAQMD's New Source Review (NSR) program for sources of Toxic Air Contaminant (TAC) emissions.  The rule requires health risk assessments (HRAs) to be conducted for projects with emissions above certain thresholds and outlines procedures for calculating TAC emissions and preparing HRAs from projects.  Ultimately, the rule reduces potential TAC emissions by requiring best available control technology for toxics (TBACT) for certain projects.  In 2015, California's Office of Environmental Health Hazard Assessment (OEHHA) updated its HRA Guidelines to account for recent advances in science related to air toxic sensitivity in children.  The California Air Resources Board (CARB) and the California Air Pollution Control Officers Association (CAPCOA) adopted an updated Risk Management Guidance Document in response to the changes in OEHHA's HRA Guidelines.  The primary purpose for the proposed revisions to Rule 2-5 is to incorporate the changes from OEHHA's 2015 HRA Guidelines, and CARB and CAPCOA's 2015 Risk Management Guidelines.  Overall, the proposed revisions to Rule 2-5 increase the stringency of BAAQMD's Toxic NSR Program.

Specifically, the following are revisions to Rule 2-5 that BAAQMD is proposing:

  • Relocating the table of TAC emission rate trigger levels to BAAQMD's Permit Handbook to allow for quicker updates of these trigger levels in the future;
  • Lowering the acute and chronic emission rate trigger levels for most TACs.  This will result in more projects requiring HRAs.
  • Incorporating a reference to BAAQMD's HRA guidelines containing the most recent OEHHA and CARB/CAPCOA literature/guidelines.  For most TACs, this will result in an increase in the predicted cancer risk by 40% for the same level of emissions when compared to the cancer risk predicted using BAAQMD's existing HRA guidelines.  For some TACs, the increase in cancer risk could be significantly greater than 40%.
  • Simplify TAC emission calculation procedures for modified sources by using total post-modification emission rates as the basis for the HRA which eliminates the need to calculate baseline TAC emissions in most cases.

BAAQMD is hosting open houses in Late January and early February to discuss revisions to the proposed rule.  More information about the open house schedule can be found here.  BAAQMD is accepting comments on the proposed revisions until March 9, 2015.  If you have any questions on the proposed revisions, or would like assistance with comment preparation, please contact Melissa Hillman at Trinity's Oakland office at (510) 285-6351.