Prevention of Significant Deterioration (PSD) and Nonattainment New Source Review (NNSR): Aggregation; Reconsideration

In this action, the Environmental Protection Agency (EPA) is concluding the reconsideration of an earlier action that the EPA published on January 15, 2009, titled "Prevention of Significant Deterioration (PSD) and Nonattainment New Source Review (NSR): Aggregation and Project Netting." The 2009 action--hereafter referred to as "2009 NSR Aggregation Action"--clarified implementation of the New Source Review (NSR) permitting program under the Clean Air Act (CAA or Act) with respect to treating related physical or operational changes as a single "modification" for the purpose of determining NSR applicability at a stationary source. On April 15, 2010, the EPA proposed to revoke the 2009 NSR Aggregation Action. After a review of the public comments received on that proposal, the EPA has now decided to not revoke the 2009 NSR Aggregation Action. The EPA is, therefore, retaining the interpretation set forth in the 2009 NSR Aggregation Action, while not adopting any changes to the relevant rule text. At the same time, the EPA is using this present action to clarify the implications of the 2009 NSR Aggregation Action for EPA-approved permitting programs. This action also lifts the administrative stay and announces the effective date of the 2009 NSR Aggregation Action.