The U.S. Environmental Protection Agency (EPA) revised its Once In Always In (OIAI) policy on January 25, 2018. This long-standing policy stated that a major source of hazardous air pollutants (HAPs) must become an area source by taking a synthetic minor limit, prior to the first substantive compliance date of an applicable major source rule under 40 CFR Part 63 - National Emissions Standards for Hazardous Air Pollutants (NESHAP), or forever be classified as a major source, even if a source's potential to emit (PTE) subsequently fell below the HAP major source thresholds.

On July 26, 2019, the EPA proposed amendments to the General Provisions of NESHAP that codify the changes to the OIAI policy by allowing existing major sources to be reclassified as area sources at any time by taking a limit on HAP PTE. In order for a major source to reclassify as an area source, the following must be met:

  1. Limit PTE HAP below the major source threshold of 10 tons per year (tpy) of any single HAP or 25 tpy of any combination of HAP.
  2. Notify the Administration following the requirements under 40 CFR 63.9, as amended, which include providing a summary of any standards to which the source becomes subject under the new classification and electronic submission through the Compliance and Emissions Data Reporting Interface (CEDRI).

In order to make certain that compliance is achieved throughout the reclassification process, EPA has incorporated applicability text that declares that the source is subject to all area source requirements immediately upon becoming an area source, and must still meet major sources requirements for the time that the source was classified as major. Similarly, if the owner decides to revert back to a major source, the source is immediately subject to the major source requirements.

To ensure that PTE calculations and limits used to determine reclassification are legally and practicably enforceable, EPA has also incorporated a change to the definition of “potential to emit” in the General Provisions of the NESHAP regulations, 40 CFR 63.2. The proposed change removes the “federally enforceable” language from the definition of PTE, replacing it with “legally and practicably enforceable”, and adds specific definitions of “legally enforceable” and “practicably enforceable”.

You may consider reclassifying your source if you fall into one of the following categories:

  1. Existing major sources that would need to obtain enforceable limits on their HAP PTE to fall below major source thresholds
  2. Existing area sources, previously classified as major sources for a specific major source NESHAP, that already have obtained enforceable limits on their HAP emissions, such that the source's PTE, as well as actual emissions are currently below major source thresholds for each individual HAP, and any combination of HAP
  3. Existing sources previously classified as major sources for a specific major source NESHAP that are no longer physically or operationally able to emit HAP in amounts that exceed the major source thresholds (commonly known as true or natural area sources)

Benefits to reclassification will vary by source, and it is up to the owner to determine if the reclassification is worthwhile. The proposed change may provide an incentive for your company to invest in cleaner technologies, new raw materials, or additional control devices, which themselves have the ability to reduce fuel and save money. The regulations to which the source is subject will change as well. There may be a monetary benefit to the change in applicability, and the compliance structure may work better for your company.

A public hearing was held August 15, 2019 on the proposed reclassification under Section 112 of the CAA, and comments must be received on or before September 24, 2019.

A copy of the proposal and rule background can be found on the Federal Registry or EPA websites. For more information, including applicability differences, please contact your local Trinity office at (800) 229-6655.