On January 25, 2018, the U.S. Environmental Protection Agency (“USEPA”) issued guidance withdrawing the “once in always in” policy for the classification of major sources of hazardous air pollutants (“HAPs”) under section 112 of the Clean Air Act.  Under the new guidance, sources of HAPs previously classified as major sources may be reclassified as area sources when the facility limits its potential to emit below major source thresholds.

The guidance supersedes the “once in always in” policy that had been in place since May 1995, shortly after promulgation of the HAPs MACT rule.  Its rescission should provide incentive for HAPs reduction at facilities that are major sources by virtue of HAPs emissions.

The policy memorandum finds that the 1995 policy memorandum is contrary to the plain language of the Clean Air Act, which the current EPA interprets to not contain a time limit on when a facility emits or has the potential to emit HAPs in excess of regulatory thresholds.

USEPA intends to publish the memorandum in the Federal Register for comment but has commenced implementing it.  The EPA page addressing the policy can be found here: https://www.epa.gov/stationary-sources-air-pollution/reclassification-major-sources-area-sources-under-section-112-clean