Huntington County, Indiana was designated nonattainment under Round 3 of the area designations for the 2010 primary Sulfur Dioxide (SO2) National Ambient Air Quality Standard (NAAQS). The Clean Air Act (CAA) directs any areas designated nonattainment by this rule to undertake certain planning and pollution control activities to attain the NAAQS as expeditiously as practicable. The state of Indiana has submitted a petition for reconsideration of this nonattainment designation. In this action, the EPA is reconsidering this designation through a notice and comment rulemaking. The EPA will, following a full evaluation of new information raised by the petition, determine an appropriate proposed designation upon reconsideration. The EPA would then provide an opportunity for new air quality information to be submitted by the state or a third party during the comment period. After reviewing all information submitted, the EPA will finalize an appropriate designation for the area, which may result in retaining the initial nonattainment designation, or if there is sufficient information to warrant a different result, may result in changing the initial designation to attainment/unclassifiable.