Smoke School Information in Maine

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

Pending Acceptance.

Maine Visible Emissions / Opacity Standard

The opacity limit for Maine is No single general number - equipment-type menu on 6-min block averages: most fuel-burning equipment 30% per Sec. 3(A)(6); stationary IC engines and combustion turbines 20% per Sec. 3(A)(4); wood/biomass and multi-fuel boilers 30% per Sec. 3(A)(5)(a); asphalt-plant baghouses 20% per Sec. 3(B)(1); rock crushers 10% per Sec. 3(B)(2), as established under 06-096 CMR Ch. 101, Sec. 3 (effective Jan 1, 2020).

Compliance is demonstrated via EPA Method 9 (40 CFR Part 60, Appendix A).

Averaging period: 6-min block averages; 2019 rewrite replaced numeric SSM exceedance allowances with work-practice standards (Sec. 4)

Maine's Chapter 101 sets opacity limits for fuel burning equipment, process sources, and fugitive emissions. 20% is the general standard on a 6-minute block average. Proposed revisions have aimed to eliminate some time-exception provisions.

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.