EPA is taking direct final action to approve revisions to the State Implementation Plan (SIP) submitted by the North Carolina Department of Environment and Natural Resources (NCDENR) on behalf of the State of North Carolina on April 16, 2001, April 4, 2003, and December 14, 2004. The purpose of these revisions is to require that continuous emissions monitoring systems be used to determine compliance; specify a 24-hour block averaging time for sulfur dioxide emissions; make a correction to a cross-reference; provide options for supplying missing data and for determining heat input; and make several revisions to permit exemptions. This action is being taken pursuant to section 110 of the Clean Air Act (CAA).