EPA Approves Indiana's Factory NOX Pollution Tracking Plan
Published Date: 4/21/2025
Proposed Rule
Summary
The EPA wants to approve Indiana’s updated plan for tracking and reporting nitrogen oxide (NOX) pollution from big factories that aren’t power plants. This change helps keep the air cleaner by using new, approved ways to monitor emissions. People and businesses involved with these factories should know comments are open until May 21, 2025, but no new costs are expected.
Analyzed Economic Effects
3 provisions identified: 3 benefits, 0 costs, 0 mixed.
Indiana allows alternative NOX monitoring
If you operate a large non-EGU (large industrial boiler, combustion turbine, or similar unit) in Indiana subject to the NOX SIP Call, Indiana’s revised rule 326 IAC 10-2-8.5 would let you use alternative monitoring methods instead of 40 CFR part 75. Permissible methods explicitly include: (A) NOX emission rate monitoring under 40 CFR part 60 combined with heat input data, (B) part 75 monitoring but with reporting to IDEM instead of EPA, (C) part 60 emission rate monitoring combined with fuel flowmeter data, and (D) heat input/fuel use plus approved emission factors (with fuel meters calibrated per manufacturer or 40 CFR part 75/98). To use an alternative you must apply via an operating permit (326 IAC 2); report ozone-season NOX mass emissions to IDEM by April 15 following the ozone season; keep records at least five years; perform stack tests at least every five years (and an initial stack test within 90 days of permit issuance if no test within the prior two years); report stack test results within 45 days; and submit a permit modification within 60 days if a test indicates an emissions factor needs upward adjustment.
EPA says no new costs to small entities
EPA states that this approval merely adopts State law and "does not impose additional requirements beyond those imposed by State law." The action is certified as "not having a significant economic impact on a substantial number of small entities" under the Regulatory Flexibility Act and "does not impose an information collection burden" under the Paperwork Reduction Act.
Existing NOX cap and air quality status preserved
EPA notes Indiana’s existing collective ozone-season NOX emissions cap for the covered non-EGUs is 8,008 tons and that the highest annual collective emissions since 2019 were 2,910 tons (2019) and 2,251 tons for 2023, showing a compliance margin. EPA proposes to find the SIP revision will not change those emission budgets and will not interfere with attainment or maintenance of the National Ambient Air Quality Standards (NAAQS).
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