The US EPA Reverses “Once In/Always In” Emission Permitting Policy

In the November 19, 2020 edition of the Federal Register, the Environmental Protection Agency issued a final rule reversing the “once in/always in” policy. The purpose of this rulemaking is to reverse the policy interpretation that once a facility is classified as a major source for hazardous air pollutants (HAP) based upon its potential to emit, it could not revert to an area source by reducing its emissions. The effective date for this final rule is January 19, 2021.

In 2019, the EPA proposed to revise the general provision that apply to the National Emission Standards for Hazardous Air Pollutants (NESHAP) to implement the plain language reading of the “major source” and “area source” definitions of the Clean Air Act (CAA) section 112 and provide that a major source can be reclassified to area source status at any time upon limiting its potential to emit hazardous air pollutants to below the major source threshold of 10 tons per year (tpy) of any single HAP and 25 tpy of any combination of HAPs.

After this rulemaking goes into effect, a major source may become an area source at any time upon reducing its emissions of and potential to emit hazardous air pollutants. A major source reclassifying to area source status remains subject to any applicable major source NESHAP requirements until the reclassification becomes effective. The EPA expects that the process for sources to reclassify to area source status for HAP will rely on existing programs under the Clean Air Act (CAA). After reclassification, the source is subject to any applicable area source NESHAP. For sources that reclassify from major to area source status and then revert back to their previous major source status, that source is subject to the applicable major source NESHAP requirements immediately upon exceeding the threshold to qualify as a major source again.

Where a major source is reclassified to area source status or an area source reverts to major source status, the owner or operator must comply with the initial notification requirements (found in section 63.9(b) and (j)) and notify the EPA of any change in the provided information. In addition, through this rulemaking the EPA clarified that a source may not be exempt from electronic reporting and removed the time limit for record retention so sources that obtain enforceable PTE limits after the effective date of this final rule are required to keep the applicability determination records as long as they rely on the PTE limits to be area sources.

The EPA believes it is authorized to reverse the once in/always in policy based on its conclusion that the statutory definitions of major source and area source contain no language fixing a source’s status at any particular point in time and contain no language suggesting a cutoff date after which the source’s status cannot change. While this final rule will go into effect January 19, 2021, there is a strong possibility the rulemaking will be undone by the new administration or through the courts.


Sources:EPA Final Rule, Reclassification of Major Sources as Area Sources Under Section 112 of the Clean Air Act (Nov. 19, 2020). 


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