Prevention of Significant Deterioration (PSD) and Nonattainment New Source Review (NSR): Aggregation

The Environmental Protection Agency (EPA) is taking final action on a rule that amends and delays the effective date for the rule addressing "aggregation" under the Prevention of Significant Deterioration (PSD) and the nonattainment New Source Review (nonattainment NSR) programs (collectively, "NSR"). The "NSR Aggregation Amendments" were published in the Federal Register on January 15, 2009, and described when a source must combine nominally- separate physical changes and changes in the method of operation for the purpose of determining whether they are a single change resulting in a significant emissions increase. On January 30, 2009, the Natural Resources Defense Council (NRDC) submitted a petition for reconsideration (the "NRDC Petition") of the NSR Aggregation Amendments. In response to the NRDC Petition, EPA announced on February 13, 2009, that it would convene a reconsideration proceeding for the NSR Aggregation Amendments and would delay the effective date of the rule from February 17, 2009 until May 18, 2009. On March 18, 2009, EPA proposed an additional delay of the effective date and solicited comment on the duration of the additional delay. By this rule, EPA is delaying the effective date of the NSR Aggregation Amendments for an additional 12 months, which will allow for sufficient time to conduct the reconsideration proceeding. The new effective date of the rule is May 18, 2010.