The Environmental Protection Agency (EPA) is taking final action to approve a portion of a revision to the North Carolina State Implementation Plan (SIP) submitted by the State of North Carolina through the North Carolina Department of Environmental Quality (formerly the North Carolina Department of Environment and Natural Resources (NCDENR)), Division of Air Quality, through a letter dated March 24, 2006. The revision includes changes to permitting regulations. The revision is part of North Carolina's strategy to meet and maintain the national ambient air quality standards (NAAQS). This action is being taken pursuant to the Clean Air Act (CAA or Act) and its implementing regulations.