Approval and Promulgation of Implementation Plan; Wisconsin

The EPA is approving revisions to Wisconsin's State Implementation Plan (SIP) regarding the control of nitrogen oxide (NO<INF>X</INF>) emissions submitted on May 25,2004. On August 29, 2003, the EPA published a final rulemaking approving the emission averaging program for existing sources subject to the state's rule limiting NO<INF>X</INF> emissions in southeast Wisconsin. The SIP revisions modify language to clarify which sources are eligible to participate in the NO<INF>X</INF> emission averaging program. In addition, the revision creates a separate categorical emission limit for new combustion turbines burning biologically derived gaseous fuels.