02.13.2018 EPA Ends “Once In, Always In” Policy For Sources That Emit Hazardous Air Pollutants By: John M. "Jay" Holloway, III

Since 1995, EPA has followed a policy that any air emissions source that emits one or more hazardous air pollutants (“HAPs”) above major source emissions thresholds is always considered a major source of HAPs. This is so even if the source subsequently decreases its HAP emissions below major source thresholds. This “once in, always in” policy is not derived from the Clean Air Act, but is only a policy position. EPA recently reversed this policy in a guidance memorandum from William L. Wehrum, the Assistant Administrator for Air and Radiation. In issuing the memo, Wehrum said that “[t]he guidance is based on a plain language reading of the [Clean Air Act] that is in line with EPA’s guidance for other provisions of the Act.”

EPA now takes the position that a major source of HAPs can accept permit limits on its emissions of HAPs and no long be a major source. By no longer being a major source, facilities will avoid extremely complex regulatory requirements. EPA’s change in how it addresses these sources “will reduce regulatory burdens for industries and states, while continuing to ensure stringent and effective controls on hazardous air pollutants,” Wehrum said.

EPA’s new stance presents a tremendous opportunity for many industrial sources and electric generating units to streamline existing permits and ease regulatory burdens. In addition, many facilities are struggling with the burden of regulators adopting a “once in, always in” position for Title V major air pollution sources (not just for HAPs). There are increasing opportunities to work with states to convert such sources into minor sources and avoid ongoing Title V permitting requirements. Facilities that no longer exceed major source thresholds should consider pursuing these opportunities.


Reclassification of Major Sources as Area Sources under Section 112 of the Clean Air Act (EPA January 25, 2018); 83 Fed. Reg. 5543 (February 8, 2018)