On January 25, 2018, Bill Wehrum, the new Assistant Administrator of US EPA’s Office of Air and Radiation, issued a memorandum to all Regional Air Division Directors rescinding US EPA’s historic “Once In Always In” (OIAI) policy for major sources under US EPA’s National Emission Standards for Hazardous Air Pollutants (NESHAP) program. Under the “Once In Always In” (OIAI) … Continue Reading