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EPA Publishes Proposed Reversal of the “Once in, Always In” Policy for Major Source NESHAPs

On June 25, 2019, EPA proposed a new rule to allow reclassification of major sources as area sources by adopting enforceable limits below applicability thresholds for major source NESHAPs.  The rule follows the January 2018 guidance memorandum issued by EPA that discussed how the May 1995 Seitz Memorandum, commonly known as the “once in, always in” (OIAI) policy, contradicts the Clean Air Act (CAA) by requiring area sources that were once major sources to continue complying with major source MACT standards, even if potential emissions were reduced below the major sources thresholds.   The basis for the previous stance was that that this requirement would ensure that HAP emissions reductions would not be reversed over time.

The CAA specifically defines a major source as a source that has the potential to emit 10 TPY or more of a single HAP or 25 TPY or more of any combination of HAP.  An area source is defined as any source with potential emissions below the same thresholds, with no reference to a deadline or compliance date.  The guidance stated that therefore, EPA did not have the authority to impose a deadline by which a source could elect to add measures to reduce or restrict emissions below the applicability thresholds. 

As a result, in the proposed rule EPA clarifies the requirements that major sources must meet in order to take on a legally enforceable limit and reclassify as an area source after the initial compliance date of an applicable NESHAP standard.  EPA is also proposing to revise the definition of “potential to emit” and add definitions for “legally and practicably enforceable” in 40 CFR 63.2.  The proposed changes would remove the requirement that HAP PTE must be federally enforceable and allow source capacity to be restricted through add-on control equipment, hours of operation, raw materials, and fuels as part of the design if the limit or emissions impact is “legally and practically” enforceable. 

Upon reclassification, the area source would then immediately become subject to any applicable area source requirements if the initial compliance date has already passed.  If the source return to major status, the major source NESHAP would then also be immediately applicable.  All notifications, including any notifications of reclassification, will need to be submitted via EPA’s CEDRI.

With this action, EPA also proposes to revise several NESHAPs that specify the date by which a major source can become an area source or that specify the date by which the initial notification must be submitted.

More information about the proposed rule can be found on the EPA website: https://www.epa.gov/stationary-sources-air-pollution/reclassification-major-sources-area-sources-under-section-112-clean.

For more information on how this might impact your operations, please contact your EPS consultant.

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