Smoke School Information in Washington

Washington Acceptance Status for VirtualOpacity^® — EPA ALT-152A

Accepted.

Washington Acceptance Letter (ORCAA / Olympia Region) »
Washington Acceptance Letter (Seattle Air District / PSCAA) »

Washington Visible Emissions / Opacity Standard

The opacity limit for Washington is 20% opacity for more than 3 min in any one hour prohibited, determined by Ecology Method 9A (cumulative method, not standard EPA Method 9); soot blowing/grate cleaning alternative: 40% for <=15 min per 8 consecutive hrs with notice to permitting authority, as established under WAC 173-400-040(2); category standards WAC 173-400-070 (e.g., catalytic cracking 40%).

Compliance is demonstrated via Ecology Method 9A (equivalent to EPA Method 9).

Averaging period: Ecology Method 9A (violation = >3 cumulative minutes over 20% per hour); alternative opacity limits available per -081/-082

Washington uses 'Ecology Method 9A' which is equivalent to EPA Method 9. Regional clean air agencies may have additional rules.

Last verified July 8, 2026

Note: Regulations change — always verify current requirements with your state's air quality agency before making compliance decisions. This page is for informational purposes and is not legal advice; consult a qualified attorney or environmental compliance professional for guidance specific to your facility.