Air Plan Approval; 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 approving a state implementation plan (SIP) revision submitted by the Pennsylvania Department of Environmental Protection (PADEP) on behalf of the Allegheny County Health Department (ACHD). The SIP revision, submitted on October 3, 2017, provides for attainment of the 2010 sulfur dioxide (SO<INF>2</INF>) primary national ambient air quality standard (NAAQS) in the Allegheny Pennsylvania SO<INF>2</INF> nonattainment area (hereafter referred to as the "Allegheny Area" or "Area"). The SIP submission includes an attainment plan, including an attainment demonstration showing SO<INF>2</INF> attainment in the Area, an analysis of reasonably available control technology (RACT) and reasonably available control measures (RACM) requirements, enforceable emission limitations and control measures, a reasonable further progress (RFP) plan, and contingency measures for the Allegheny Area. EPA is approving new SO<INF>2</INF> emission limits and associated compliance parameters for the four major sources of SO<INF>2</INF> in the Allegheny Area into the Allegheny County portion of the Pennsylvania SIP. Three of the sources (Clairton Coke Works, Edgar Thomson, and Irvin Works) are collectively known as the U.S. Steel (USS) Mon Valley Works, and the fourth is the Harsco Metals Facility, also referred to as Braddock Recovery. EPA is also approving the base year emissions inventory for the Allegheny Area and ACHD's certification that the nonattainment new source review (NNSR) permit program meets requirements. These revisions to the Pennsylvania SIP are in accordance with the requirements of the Clean Air Act (CAA).