Finding of Failure To Attain; Air Plan Approval; Indiana; Huntington County Sulfur Dioxide Attainment Plan

The Environmental Protection Agency (EPA) is determining that the Huntington County, Indiana nonattainment area failed to attain the 2010 Sulfur Dioxide (SO<INF>2</INF>) National Ambient Air Quality Standard (NAAQS) by the applicable attainment date of April 9, 2023. EPA is also approving revisions into the Indiana State Implementation Plan (SIP) intended to provide for attainment of the 2010 SO<INF>2</INF> NAAQS for the Huntington County nonattainment area. These SIP revisions include Indiana's attainment demonstration and other planning elements required under the Clean Air Act (CAA), and an order issued by the Commissioner of the Indiana Department of Environmental Management containing enforceable emission limits. Further, EPA is determining that the provisions of Indiana's SIP submittal adequately provide for attainment of the NAAQS and that the plan meets all other applicable CAA requirements. EPA proposed to approve this action on June 18, 2025, and received no adverse comments.