The Environmental Protection Agency (“EPA”) recently issued a guidance memorandum withdrawing the decades-old “once in, always in” policy. The policy prohibited facilities once considered to be major sources of emissions of hazardous air pollutants to be later reclassified. These facilities are always subject to the class Maximum Achievable Control Technology (“MACT”) standards, regardless of any newly implemented processes or controls that reduce emissions.
However, the EPA found that the policy was established upon an incorrect interpretation of the Clean Air Act. Facilities may now be reclassified as “area sources” if their emissions fall below the threshold and will be subject to less strict standards.