Approval of Air Quality Implementation Plans; Wisconsin; Partial Disapproval of “Infrastructure” State Implementation Plan

Pursuant to its authority under the Clean Air Act (CAA), EPA is taking final action to disapprove two narrow portions of submissions made by the Wisconsin Department of Natural Resources (WDNR) to address the section 110(a)(1) and (2) requirements of the CAA, often referred to as the "infrastructure" State Implementation Plan (SIP). Specifically, we are finalizing the disapproval of portions of WDNR's submissions intended to meet certain requirements of section 110(a)(2)(C) with respect to the 1997 8-hour ozone National Ambient Air Quality Standards (NAAQS) and 1997 24-hour PM<INF>2.5</INF> NAAQS. Among other conditions, section 110(a)(2)(C) of the CAA requires states to correctly address oxides of nitrogen (NO<INF>X</INF>) as a precursor to ozone in their respective prevention of significant deterioration (PSD) programs. EPA is finalizing disapproval of a portion of Wisconsin's submissions intended to satisfy this requirement. EPA is also finalizing disapproval of a portion of Wisconsin's submissions because the SIP currently contains a new source review (NSR) exemption for fuel changes as major modifications where the source was capable of accommodating the change before January 6, 1975. The proposed rule associated with this final action was published on April 20, 2012.