EPA has completed a reconsideration of a 2009 action to clarify “project aggregation” for the major New Source Review (NSR) permitting program. This action affirms the Agency's 2009 interpretation of when physical or operational changes should be combined into a single “project” for analysis of major NSR applicability. This action also lifts the administrative stay of the 2009 action and explains how the 2009 action applies to states with approved permitting programs. Read a prepublication version of the notice and a summary fact sheet below.

• Prevention of Significant Deterioration (PSD) and Nonattainment New Source Review (NNSR): Aggregation; Reconsideration (PDF)(37 pp, 401 K)
  (prepublication notice)
• Fact Sheet: Prevention of Significant Deterioration (PSD) and Nonattainment New Source Review (NNSR): Aggregation; Reconsideration (PDF)(2 pp, 181 K)