EPA Proposes Okay for Louisville Ozone Maintenance Plan
Published Date: 8/27/2026
Proposed Rule
Summary
The EPA is proposing to approve Kentucky’s plan to keep the air clean in the Louisville area by maintaining safe ozone levels through 2046. This plan affects Bullitt, Jefferson, and Oldham counties and makes sure pollution rules stay strong without extra costs. People can share their thoughts on this plan until September 17, 2026.
Analyzed Economic Effects
4 provisions identified: 2 benefits, 1 costs, 1 mixed.
Contingency Triggers That Can Trigger Controls
The Louisville Area LMP says the Division will evaluate controls if any 8-hour ozone monitoring reading is 0.085 ppm or greater or if emissions inventories show over 10 percent growth in NOX or VOCs compared to the attainment inventory. Implementation of necessary controls in response to an initial indicator must occur no later than 12 months after the conclusion of the ozone season (October 31) in which the indicator occurred, and contingency measures must be in place within 24 months of a monitored violation (three-year average of annual fourth-highest values of 0.085 ppm or greater).
List of Potential Contingency Measures
The LMP lists potential contingency measures that could be selected if triggers occur, including adoption of Reasonably Available Control Technology (RACT) for point sources, enhanced stationary-source inspections, fuel programs, vehicle/road restrictions or HOV lanes, trip-reduction ordinances, employer transportation management plans, pedestrian/non-motorized infrastructure, modern vehicle inspection/maintenance programs, diesel retrofit programs (including incentives for fleet retrofits), and engine idling reduction programs.
Louisville Air Plan Keeps Ozone Limits
The EPA proposes to approve Kentucky’s Limited Maintenance Plan (LMP) that keeps the 1997 8-hour ozone National Ambient Air Quality Standard in the Kentucky portion of the Louisville area (Bullitt, Jefferson, and Oldham counties) through 2027. If approved, the plan’s commitments become federally enforceable as part of the Kentucky State Implementation Plan (SIP).
EPA Finds No Major Small-Business Burden
In this proposed approval, the EPA states the action "does not impose additional requirements beyond those imposed by State law" and is "certified as not having a significant economic impact on a substantial number of small entities" under the Regulatory Flexibility Act.
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Key Dates
Department and Agencies
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Next: 2026-17502, Air Plan Approval; Kentucky; Cincinnati-Hamilton Area Limited Maintenance Plan for the 1997 8-Hour Ozone NAAQS
The U.S. Environmental Protection Agency (EPA or Agency) is proposing to approve a State Implementation Plan (SIP) revision submitted by the Commonwealth of Kentucky through the Energy and Environment Cabinet (Cabinet), Division of Air Quality (Division), on July 23, 2024. The SIP revision consists of a Limited Maintenance Plan (LMP) for the Kentucky portion of the tri-state Cincinnati-Hamilton 1997 8-hour ozone nonattainment area (the "tri-state Cincinnati-Hamilton Area"). The Kentucky portion of the tri-state Cincinnati-Hamilton Area is composed of Boone, Campbell, and Kenton Counties in Kentucky (hereinafter also referred to as the "Northern Kentucky Area"). The EPA is proposing to approve Kentucky's LMP for the Northern Kentucky Area because it provides for the maintenance of the 1997 8-hour ozone National Ambient Air Quality Standards (NAAQS) within the tri-state Cincinnati-Hamilton Area through the end of the second 10-year portion of the maintenance period. The effect of this proposed action would be to make certain commitments related to maintenance of the 1997 8-hour ozone NAAQS in the Northern Kentucky Area federally enforceable as part of the Kentucky SIP.