On January 25, 2018, the Environmental Protection Agency (EPA) withdrew its longstanding but controversial “once in, always in” policy that a “major source” of hazardous air pollutants (HAP) was forever locked into “major source” status – and compliance with HAP major source regulations – upon the first compliance date of the regulations. As a result, sources that have been deemed major sources of HAP may now want to reassess their options, and consider whether reclassification to non major status would be feasible and effective.