Jettisoning 23-year old doctrine, the U.S. Environmental Protection Agency (EPA) announced last week in guidance (“Reclassification of Major Sources as Area Sources Under Section 112 of the Clean Air Act,” Memorandum from William L. Wehrum, EPA (January 25, 2018)) that it was abandoning its “once-in-always-in” (OIAI) policy that branded stationary air pollution sources as “major sources” in perpetuity for purposes of compliance with the Clean Air Act’s “maximum available control technology” (MACT) standards.
