Indiana Sulfur Dioxide Air Quality Plan Approval
Summary
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.
Compliance Requirements
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The Huntington County, Indiana nonattainment area must submit a revision to its SIP to provide for attainment of the 2010 SO2 NAAQS no later than five years from the date of any final determination that the area failed to attain.; Indiana's November 6, 2023, SIP attainment plan submittal and February 12, 2024, supplemental SIP revision for the Huntington County SO2 nonattainment area must be approved as fulfilling the requirement to provide for attainment of the 2010 SO2 NAAQS.; Isolatek International must comply with the enforceable emission limits and associated requirements as contained in Commissioner’s Order 2023-Air-02.
Deadline: Five years from the date of final determination of failure to attain
Market Impacts
The EPA's determination that the Huntington County, Indiana nonattainment area failed to attain the 2010 SO2 NAAQS by the applicable attainment date of April 9, 2023, imposes restrictions on emissions in the area. This includes enforceable emission limits and associated requirements for Isolatek International.; The requirement for Indiana to submit a revision to its SIP to provide for attainment in the Huntington County area no later than five years from the date of any final determination that the area failed to attain creates opportunities for environmental consulting and compliance services.
Validated Company Impacts
Celanese Corp
Celanese Corp operates as a global chemical and specialty materials company producing acetyl products, engineered materials, and acetate tow, with no operations or facilities in Huntington County, Indiana. The rule specifically targets SO2 emissions compliance for the Huntington County nonattainment area and Isolatek International, making it geographically and operationally irrelevant to Celanese's business activities. The rule directly impacts the company's environmental regulations risk factor, which is explicitly identified as having potential for significant liability and increased compliance costs. The enforceable SO2 emission limits and associated requirements for Isolatek International create immediate compliance obligations that align precisely with this disclosed regulatory risk.