EPA Eliminates “Once In, Always In” Policy for Major Air Sources

Power Plant
November 10, 2020

Recently, the EPA finalized new verbiage to the Clean Air Act that allows major sources of hazardous air pollutants (HAP) to reclassify as area sources at any time  — provided that the facility has reduced hazardous air emissions to below the major source thresholds (MST) of 10 tons per year (tpy) of any single HAP or 25 tpy of any combination of HAP.

According to the EPA, this action reduces “the regulatory burden and provides a level of fairness and flexibility for sources that reduce HAP emissions below major source thresholds.”

The rule reverses the 1995 Seitz Memorandum “Once-In, Always-In” policy, which required a major source to be subject to Title V permitting and meet maximum achievable control technology (MACT) standards throughout its lifetime, regardless of future emission rates.

Reclassification, according to EPA, will allow companies to eliminate the intense monitoring, record keeping, and reporting associated with being a major source, helping reduce compliance and financial obligations.

Currently 7,183 facilities, particularly refineries and plants emitting pollutants such as lead, arsenic, and mercury, are subject to major source emissions standards.

EPA estimates that about one-third of these emit HAP below the required 75% threshold (below 7.5 tpy for one HAP and 18.75 tpy for all HAP).

If all of these facilities reclassified as area sources, the EPA calculated that the initial permitting costs could result in overall net costs of $16.1 million in the first year. After that, however, these reclassifications could result in a savings of around $90.6 million (both in 2017 dollars).

EPA expects that three general types of sources may seek to reclassify:

  1. Sources previously classified as major that are no longer physically or operationally capable of emitting HAP in amounts that exceed the MST.
  2. Sources previously classified as major that obtain enforceable PTE limits or that already have existing enforceable PTE limits that keep HAP emissions below the MST.
  3. Sources with actual emissions above the MST that (1) reduce emissions to below the MST and (2) obtain enforceable PTE limits that keep HAP emissions below the MST.

Emissions requirements will not change for existing major sources that choose not to reclassify.


A company which chooses to reclassify a major source to area source status remains subject to applicable major source requirements until the reclassification becomes effective.

Becoming an area source does not absolve a source subject to an enforcement action or investigation for any current major source violations or infractions.

A notification of reclassification must contain the following information:

  1. The name and address of the owner or operator.
  2. The address (i.e., physical location) of the affected source.
  3. An identification of the standard being reclassified from and to (if applicable).
  4. Date of effectiveness of the reclassification.

Electronic submissions may be required under some circumstances via the EPA’s CEDRI, which can be accessed through EPA’s central data base exchange (CDX) at https://cdx.epa.gov/.

Compliance dates are source dependent. According to the ruling: “After the effective date of a relevant standard established under this part pursuant to section 112(d) or 112(h) of the Act, the owner or operator of an existing source shall comply with such standard by the compliance date established by the Administrator in the applicable subpart(s) of this part, except as provided in §63.1(c)(6)(i). Except as otherwise provided for in section 112 of the Act, in no case will the compliance date established for an existing source in an applicable subpart of this part exceed 3 years after the effective date of such standard.”

Don’t get too comfortable with the new ruling just yet, though. Environmental groups such as the Sierra Club and Natural Resources Defense Council are not happy. They believe this action violates the CAA and plan to file suit against the EPA.

For more information about the rule, go to https://www.epa.gov/sites/production/files/2020-10/documents/frn_mm2a_2060-am75_final_rule.pdf

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