The Environmental Protection Agency (EPA) recently issued a guidance memorandum announcing its withdrawal of their “once in always in” policy for the classification of major sources of hazardous air pollutants under section 112 of the Clean Air Act. Under the original policy, once a facility crossed over the threshold to become a “major source” of hazardous air pollutants (10 TPY of any HAP or 25 TPY of all HAPs) and became subject to a MACT standard, it would forever be regarded by EPA as a major source (therefore making it ineligible for area source standards), even if it voluntarily became a “synthetic minor” source by agreeing to legally-enforceable permit limits that kept its potential to emit HAPs below the major source threshold.
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. The policy is effective as of now, and according to the agency press release, EPA intends to publish a federal register notice for public comment to formally implement the revised policy.
Notably, the withdrawal of the “once in always in” policy was one of the issues that SOCMA called on EPA to address in comments
filed last May in response to their request for input on regulations that may be appropriate for repeal, replacement or modification, in accordance with Executive Order 1377, “Enforcing the Regulatory Reform Agenda.”