Air Plan Approval; Indiana; Attainment Plan for Indianapolis, Southwest Indiana, and Terre Haute SO2

The Environmental Protection Agency (EPA) is proposing to approve as a State Implementation Plan (SIP) revision an Indiana submission to EPA dated October 2, 2015. The submission addresses attainment of the 2010 sulfur dioxide (SO2) national ambient air quality standard (NAAQS) for the Indianapolis (Marion County), Southwest Indiana (Daviess and Pike Counties), and Terre Haute (Vigo County) areas. Indiana also submitted a SIP revision request for the Morgan County area. In this proposed action, EPA is not addressing the Morgan County portion of the SIP revision request, and will address it separately in a future action. This plan (herein called a ``nonattainment plan'') includes Indiana's attainment demonstration and other elements required under the Clean Air Act (CAA). In addition to an attainment demonstration, the nonattainment plan addresses the requirement for meeting reasonable further progress (RFP) toward attainment of the NAAQS, reasonably available control measures and reasonably available control technology (RACM/RACT), base-year and projection-year emission inventories, enforceable emissions limitations and control measures, and contingency measures. EPA proposes to conclude that Indiana has appropriately demonstrated that the plan provisions provide for attainment of the 2010 SO2 NAAQS in the Indianapolis, Southwest Indiana, and Terre Haute areas by the applicable attainment date and that the plan meets the other applicable requirements under the CAA.