EPA Approves Kentucky's SO2 Air Plan Update
Published Date: 9/25/2026
Rule
Summary
The EPA is giving a thumbs-up to Kentucky’s updated plan to keep the air clean in part of Campbell County for the next 10 years, focusing on sulfur dioxide pollution. This means the area will continue meeting air quality rules without extra costs or changes for residents and businesses. The new plan kicks in on November 24, 2026, unless someone raises concerns by October 26, 2026.
Analyzed Economic Effects
3 provisions identified: 2 benefits, 1 costs, 0 mixed.
Maintenance of SO2 Air Standard through 2037
The EPA approved Kentucky's second 10-year maintenance plan to keep the Kentucky portion of the Campbell-Clermont area meeting the 2010 1-hour sulfur dioxide (SO2) standard through 2037. This approval becomes effective November 24, 2026 unless adverse comments are received by October 26, 2026, and the plan (including its commitments) is now federally enforceable as part of the Kentucky State Implementation Plan (SIP).
No New Federal Costs for Small Businesses
EPA states this approval "does not impose additional requirements beyond those imposed by State law," is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act, and does not create new information-collection burdens. That means EPA found the rule will not impose new federal costs on small businesses as part of this approval.
Contingency Triggers Could Prompt New Controls
Kentucky's maintenance plan includes contingency measures that must be triggered and implemented if SO2 levels rise: a warning trigger occurs when an annual 99th-percentile 1-hour SO2 concentration greater than 75 ppb occurs in a single year (prompting a study and controls implemented no later than 12 months from the end of that year); an action trigger occurs when a two-year average 99th-percentile 1-hour concentration greater than 75 ppb or a three-year violation occurs (prompting additional control measures implemented within 18 months from the close of the calendar year). If adopted, such control measures would be subject to Kentucky's SIP revision process including public notice and comment.
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