EPA Greenlights Indiana's Ozone Air Plan Update
Published Date: 9/9/2026
Rule
Summary
The U.S. Environmental Protection Agency (EPA) is approving a portion of Indiana's State Implementation Plan (SIP) submission regarding the infrastructure requirements in Clean Air Act (CAA) section 110 for the 2015 ozone National Ambient Air Quality Standards (NAAQS). The infrastructure requirements are designed to ensure that the structural components of each State's air quality management program are adequate to meet the State's responsibilities under the CAA. The EPA finds that Indiana's infrastructure submission fulfills CAA requirements for a State's SIP to contain adequate provisions prohibiting emissions that will interfere with required visibility protection measures in any other State's SIP. The EPA proposed to approve this action on April 10, 2026, and received no adverse comments.
Analyzed Economic Effects
2 provisions identified: 2 benefits, 0 costs, 0 mixed.
EPA Approves Indiana Prong 4 (Visibility)
The EPA is approving Indiana's November 2, 2018 interstate transport infrastructure SIP submission for the Prong 4 (visibility) requirement of CAA section 110(a)(2)(D)(i)(II) for the 2015 ozone NAAQS. The approval finalizes the EPA's proposed action from April 10, 2026 and is effective October 9, 2026, confirming that Indiana's SIP contains provisions prohibiting emissions that would interfere with visibility protection measures in other States' SIPs.
No New Federal Costs for Indiana Small Businesses
The EPA states this approval "does not impose additional requirements beyond those imposed by State law" and the action "is certified as not having a significant economic impact on a substantial number of small entities" under the Regulatory Flexibility Act. The final rule is effective October 9, 2026, and therefore does not create new federal compliance obligations for small entities beyond existing State requirements.
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