Air Toxics in California – 2016 Update

Requirements regarding Toxic Air Contaminants (TACs) have recently become substantially more stringent for both existing facilities and new projects due to a combination of factors, including the new OEHHA Risk Assessment Guidelines that were finalized in 2015, OEHHA updates to cancer potency factors/RELs, local thresholds for maximum allowable risk (calculated based on the OEHHA guidelines/factors and dispersion models), and (in some areas) new procedures regarding emissions estimation.  This increased stringency presents challenges regarding both (a) whether or not it is even feasible to meet the new thresholds, and (b) how to communicate this risk to the public (both in general, and with regard to AB2588 notification mandates).  A&WMA's Golden West Section will be holding a conference to provide information and specific examples regarding the following issues:

  • An overview of the motivation behind the new OEHHA risk assessment guidelines, and state and local reactions to the changes.
  • A discussion of conservatism in risk assessment techniques: how are the conservative, and why.
  • A summary of how different air districts in California are implementing the new guidelines.
  • How to communicate risk to the general public in view of the changes in methodology and approach.


If you have questions regarding GWS events, or your company/organization is interested in sponsoring/exhibiting at future events, please contact Wilma Dreessen by phone at 925-335-3468, or by email at