On October 20, 2017, Oregon Department of Environmental Quality (ODEQ) released draft Cleaner Air Oregon rules. The draft rules and supporting documents can be found on ODEQ's website (link). 

The draft rules require air toxic emissions reports, risk assessments for new projects and existing facilities, and air toxic permit attachments. ODEQ is proposing a tiered implementation approach for the source risk assessments. Tier 1 implementation will take place over the first 5 years for the top 80 ranking sources when considering air toxic emissions and sensitive populations within a one kilometer radius of the source.  

ODEQ is proposing 4 levels of risk assessments to demonstrate compliance with the Risk Action Levels (RALs) for the individual source risk assessments. The source risk assessment levels range from simple and conservative to refined and complex: 

  • Level 1: Risk assessment tool (lookup table);
  • Level 2: Screening air dispersion modeling (AERSCREEN);
  • Level 3: Refined air dispersion modeling (AERMOD), and
  • Level 4: A comprehensive health risk assessment.

ODEQ also indicated that risk from natural gas/propane combustion may be excluded from the total risk calculation for the purpose of determining compliance with a RAL and reported separately.

If you have any questions regarding Oregon's Air Toxics Rulemaking Process, please contact Ashley Jones at (253) 867-5600 or avjones@trinityconsultants.com.