Reclassification of Major Sources as Area Sources

In 1995, the United States Environmental Protection Agency (US EPA) issued a memo known as the Once-in-Always-In (OIAI) policy that effectively made all major source designations permanent regardless of whether emission reductions lowered facility emissions of hazardous air pollutants (HAP) to less than major source thresholds. On January 25, 2018, the US EPA released another memo that ultimately reversed the OIAI policy to allow major source facilities to reclassify as area sources. This new memo became known as the Major MACT to Area (MM2A) policy memo. On November 11, 2020, the US EPA published a finalized rule in the Federal Register titled Reclassification of Major Sources to Area Sources Under Section 112 of the Clean Air Act that codifies the MM2A policy decision of the January 25, 2018 memo. 

Major source facilities reclassifying from a major source to an area source for HAP emissions by reducing their potential to emit (PTE) to less than 10 tons per year of any single HAP and less than 25 tons per year of any combination of HAP are required to submit an electronic notification to the US EPA through the Compliance and Emissions Data Reporting Interface (CEDRI) system. The electronic notification is due no later than February 2, 2021, if a facility reclassified as an area source after January 25, 2018, but before January 19, 2021. The notification is due within 15 calendar days after the implementation of the change if reclassification occurs after January 19, 2021. The revised notification requirements can be found be found at 40 CFR Part 63.9(j) and (k).

For information on reclassifying from a major source to area source, feel free to contact your permit writer or contact the Air Toxics section at 803-898-0341.

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