Approval and Promulgation of Implementation Plans; Wisconsin; Nitrogen Oxide Combustion Turbine Alternative Control Requirements for the Milwaukee-Racine Former Nonattainment Area

On February 24, 2014, the Wisconsin Department of Natural Resources (WDNR) submitted revisions to the limits found in its nitrogen oxides (NO<INF>X</INF>) combustion turbine rule for the Milwaukee-Racine area formerly nonattainment for the 1997 ozone standard. This revision is contained in "2013 Wisconsin Act 91--Senate Bill 371," which provides for alternative NO<INF>X</INF> requirements, subject to Environmental Protection Agency (EPA) approval on a case-by- case basis, to determine whether these alternative limits satisfy the reasonably available control technology (RACT) requirements of the Clean Air Act (CAA). EPA proposed to approve this rule as a revision to the State Implementation Plan (SIP) on April 30, 2014, and received adverse comments. EPA subsequently issued a supplemental proposal on October 9, 2014, to address the issue of whether the SIP revision satisfies certain anti-backsliding requirements of the CAA. EPA received an adverse comment on this supplemental proposal on October 23, 2014. After duly considering both this comment and the adverse comments received in response to the April 30, 2014, proposal, EPA is approving this rule because the process established will ensure that modified sources meet RACT and the revision meets the anti-backsliding requirements of the CAA. This final action addresses all of these adverse comments.