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  • Stationary Sources of Air Pollution
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Guidance for Reclassification of Major Sources as Area Sources Under Section 112 of the Clean Air Act

On January 25, 2018, EPA issued a guidance memorandum withdrawing the “once in, always in” policy for the classification of major sources of hazardous air pollutants under section 112 of the Clean Air Act.  With the new guidance, sources of hazardous air pollutants previously classified as “major sources” may be reclassified as “area sources” at any time, provided the facility limits its potential to emit below major source thresholds.

On February 8, 2018, EPA published a Federal Register notice  regarding this memorandum. 

  • Memorandum: Reclassification of Major Sources as Area Sources under Section 112 of the Clean Air Act (pdf) (4.04 MB, January 25, 2018)
    This memorandum withdraws the “once in, always in” policy.
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Last updated on July 5, 2022
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