In the August 9, 2019 edition of the Federal Register, US EPA proposed modifications to the New Source Review (NSR) applicability regulations found in 40 CFR 51 and 52. The modification will make it clear that both emissions increases and emissions decreases resulting from a proposed project will be considered when applying the NSR major modification applicability test. Comments in response to this proposal must be made by October 8, 2019.
The purpose of the rule change, according to EPA, is to clarify the requirements that apply to sources proposing to undertake a physical or operation change under the NSR preconstruction permitting program. Under the current program, an existing major source proposing to undertake a project must determine whether that project will constitute a major modification based on a two-step applicability test. If it is determined that the project is a major modification then NSR preconstruction permitting requirements apply. The first step is to determine whether the project will cause a “significant emissions increase” of a regulated NSR pollutant. If the proposed project is projected to cause such an increase, the second step is to determine if there is a “significant net emissions increase” of that pollutant. In this proposal, EPA is attempting to modify the first step to make it clear that both emissions increases and decreases resulting from proposed projects will be considered.