View Rule

On July 12, 2016, the Environmental Protection Agency (EPA) promulgated initial air quality designations for certain areas in the United States (U.S.) for the 2010 sulfur dioxide (SO2) primary National Ambient Air Quality Standard (NAAQS). It was the second of four expected sets of actions to designate areas of the U.S. for the 2010 SO2 NAAQS. In the July 12, 2016 action, Williamson County, Illinois was designated nonattainment. The nonattainment designation was based on EPA's analysis of air quality modeling submitted by Southern Illinois Power Cooperative (SIPC, owner of Marion Power Station), Sierra Club, and Illinois EPA. SIPC filed a petition for judicial review of the Round 2 designations and has twice administratively petitioned EPA to change the nonattainment designation, submitting information to support claims that the violating receptor area was and/or is under controlled access and is not ambient air. In January 2017, EPA denied SIPC's petition for reconsideration under then-Administrator McCarthy, and SIPC filed a petition for judicial review of that denial, which is consolidated with their previous challenge. In September 2017, EPA responded to SIPC's subsequent petition for error correction by indicating an intent to undertake an administrative action with notice and comment to revisit the nonattainment designation, and the D.C. Circuit granted EPA's motion to place the judicial petitions in abeyance on this basis. The area in Williamson County, IL remains nonattainment pending the outcome of EPA's intended administrative action. This action will initiate a notice and comment rulemaking to revisit the initial area designation for Williamson County, Illinois.