View Rule

Under the New Source Review (NSR) pre-construction permitting program, sources undergoing modifications need to determine whether their modification is considered a major modification and thus subject to NSR pre-construction permitting. A source owner determines if its source is undergoing a major modification under NSR using a two-step applicability test. The first step is to determine if there is a "significant emission increase" of a regulated NSR pollutant from the proposed modification (Step 1) and the second step is to determine if there is a "significant net emission increase" of that pollutant (Step 2). In this action, we are proposing the consideration of emissions increases and decreases from a modification in Step 1 of the NSR major modification applicability test for all unit types (i.e., new, existing, and hybrid units).

Statement of Need: In March 2018, the Agency issued an interpretative memorandum to clarify that we interpret our current NSR regulations to allow Project Emissions Accounting for hybrid units as well as for new and existing units. This regulation would further clarify the concept of Project Emissions Accounting for all types of emissions units.

Summary of the Legal Basis: 40 CFR 52.21

Alternatives: Alternatives will be analyzed as the proposal is developed.

Anticipated Costs and Benefits: Costs and benefits will be analyzed as the proposal is developed.

Risks: Risks will be analyzed as the proposal is developed.