Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Attainment Plan for the Allegheny, Pennsylvania Nonattainment Area for the 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard

The Environmental Protection Agency (EPA) is proposing to approve a state implementation plan (SIP) revision, submitted by the Pennsylvania Department of Environmental Protection (PADEP) on behalf of the Allegheny County Health Department (ACHD), to EPA on October 3, 2017, for the purpose of providing for attainment of the 2010 sulfur dioxide (SO2) primary national ambient air quality standard (NAAQS) in the Allegheny, Pennsylvania SO2 nonattainment area (hereafter referred to as the ``Allegheny Area'' or ``Area''). The major sources of SO2 in the Allegheny Area are the Harsco Metals facility and the facilities which comprise the U.S. Steel (USS) Mon Valley Works: Clairton, Edgar Thomson and Irvin Plants. The Pennsylvania SIP submission is an attainment plan which includes the base year emissions inventory, an analysis of the reasonably available control technology (RACT) and reasonably available control measure (RACM) requirements, enforceable emission limitations and control measures, a reasonable further progress (RFP) plan, a modeling demonstration of SO2 attainment, a nonattainment New Source Review (NNSR) permit program, and contingency measures for the Allegheny Area. As part of approving the attainment plan, EPA is also proposing to approve new SO2 emission limits and associated compliance parameters for USS Clairton, Edgar Thomson and Irvin Plants and the Harsco Metals facility into the Allegheny County portion of the Pennsylvania SIP. This action is being taken under the Clean Air Act (CAA).