In the July 26, 2019 Federal Register the Environmental Protection Agency (EPA) released its proposed rule that would amend its regulations to incorporate its repeal of the Once In, Always In policy (OIAI). The OIAI policy was rescinded in January 2018 in a memorandum. Public comments will be accepted through September 24, 2019.
EPA’s former OIAI policy detailed in a 1995 memorandum addressed the issue of when a source could be classified as an area source of hazardous air pollutants (HAPs). The OIAI policy gave sites until the first compliance date of a new Maximum Available Control Technology (MACT) standard to avoid classification as a major source of HAPs. Once the compliance date passed, a major source could not be reclassified as an area source and would always be subject to the MACT standard.
Under the proposed rule, major sources that accept potential-to-emit (PTE) HAP limits that are legally and practically enforceable can reclassify as an area source at any time. A source that is reclassified would be required to provide electronic notification of the reclassification.
In response to a court decision, the definition of PTE would be revised to remove the requirement that the limits be “federally enforceable” and instead require that limits be “legally and practicably” enforceable. This change would permit state-only enforceable limits to count as limits on PTE. Legally enforceable would be defined as an emission limitation or other standard that both identifies the legal authority under which the limitation or standard is issued and provides the right for the issuing authority to enforce it.
A practically enforceable limitation or standard must meet three criteria. It must be written so that it is possible to verify compliance and document violations when enforcement is necessary; must specify a technically accurate numerical limitation and identify the portions of the source subject to limitation which account for the type of restriction employed; and must specify the method of determining compliance, including monitoring, recordkeeping, and reporting requirements.
Finally, to account for this change in policy, many NESHAP sources will be modified to account for the fact that sources may become subject to area source standards after the first compliance deadline.