EPA Tinkers With Colorado Smog Rules Again
Published Date: 6/23/2026
Proposed Rule
Summary
The EPA is proposing to approve Colorado’s plan to control smog-causing pollution in the Denver Metro and North Front Range area. This plan updates rules for certain polluters and fixes past issues, helping the region meet clean air goals. People and businesses in this area should note the July 23, 2026 deadline to share their thoughts on the plan.
Analyzed Economic Effects
5 provisions identified: 1 benefits, 4 costs, 0 mixed.
Annual Reporting for Metal Parts Coaters
Colorado’s April 2, 2025 SIP revisions require metal parts and metal products coating sources in the Denver Metro/North Front Range area to submit an annual report showing that products used during the calendar year meet the VOC content limits. These sources must keep related records for five years and the reports are made available through the State’s Public Records Portal.
Semi-Annual Reporting for Wood Coaters
Colorado’s April 2, 2025 SIP revisions require wood products coating sources in the Denver Metro/North Front Range area to submit a semi-annual report documenting that products used during the prior semi-annual period comply with VOC content limits. Records must be kept for five years and the reporting information is available through the State’s Public Records Portal.
Semi-Annual Reports for Combustion Equipment
Colorado’s April 2, 2025 SIP revisions add a semi-annual reporting requirement for combustion equipment at major sources in the Denver Metro/North Front Range area. Affected sources must report compliance with combustion process adjustment requirements and keep records for five years; the information is accessible through the Division’s Public Records Portal.
Semi-Annual Reporting for Foam Manufacturing
Colorado’s April 2, 2025 SIP revisions require foam manufacturing operations in the Denver Metro/North Front Range area to submit semi-annual reports documenting compliance with VOC emission limits. Records must be maintained for five years and the reports are available via the State’s Public Records Portal.
Public Access to Compliance Records
The SIP revisions make the reports and related records for the listed industry rules available through the Colorado Air Pollution Control Division’s Public Records Portal, so compliance information for the Denver Metro/North Front Range area can be accessed by the public. The EPA is proposing to approve these revisions; the public comment deadline for this proposal is July 23, 2026.
Personalized for You
How does this regulation affect your finances?
Personalize government policy and PRIA will tell you what this federal register document means for your household, plus every other regulation we track. PRIA reads each provision against your financial profile to show you exactly what matters to your wallet.
Key Dates
Department and Agencies
Related Federal Register Documents
2026-19072, Rescission of the Greenhouse Gas Findings for Fossil Fuel-Fired Power Plants and Repeal of Regulations for Power Plant Greenhouse Gas Emissions Under Clean Air Act Section 111
The EPA is proposing to cancel all greenhouse gas rules for fossil fuel power plants, saying the law doesn’t let them regulate these emissions for climate reasons. This change affects power plants across the U.S. and could impact future pollution limits and costs. Comments on this proposal are open until November 2, 2026, so now’s the time to speak up!
2026-19071, Partial Repeal of the Carbon Pollution Standards for Fossil Fuel-Fired Electric Generating Units
The EPA is rolling back most of the 2024 rules that limited carbon pollution from fossil fuel power plants. This change affects coal and gas plants by easing some strict limits on emissions and carbon capture technology. The new rules kick in on November 16, 2026, potentially saving money for power plants but raising questions about pollution control.
2026-18317, Updated Definition of “Waters of the United States”
The purpose of this supplemental notice of proposed rulemaking is for the U.S. Environmental Protection Agency (EPA) and the Department of the Army ("the agencies") to supplement and seek additional comment on certain aspects of an earlier proposal, published on November 20, 2025, to revise the regulations defining the scope of waters federally covered under the Clean Water Act in light of the U.S. Supreme Court's 2023 decision in Sackett v. Environmental Protection Agency. As stated in the agencies' November 20, 2025 Notice of Proposed Rulemaking (NPRM), the agencies intend for this rulemaking to provide greater regulatory certainty and increase Clean Water Act program predictability and consistency by clarifying the definition of "waters of the United States." After consideration of the public comments received on the NPRM, the agencies are issuing this notice to supplement the NPRM with additional regulatory options on certain aspects of the proposed rule.
2026-14112, Amendments and Nonconformance Penalties for Model Year 2027 and Later Heavy-Duty Highway Engines and Amendments to Inducement Provisions for SCR-Equipped Diesel Engines
Starting with model year 2027, the EPA is updating rules for big truck engines to make sure they last longer and pollute less. They’re also letting engine makers pay penalties if their engines don’t meet standards, and tightening rules for special pollution-control systems on diesel engines. These changes affect truck and engine makers and kick in soon, with public feedback due by August 29, 2026.
2026-13667, Minor New Source Review Program Air Permitting Public Participation Requirements for State Implementation Plans
The EPA wants to give states more freedom to decide how much public input is needed when approving small air pollution sources or changes. This means local air agencies can tailor public participation to fit their community’s needs while still protecting air quality. If you’re involved in air permits, watch for comment deadlines and possible virtual hearings this summer!
2026-13263, Revisions To Establish the Sixth Unregulated Contaminant Monitoring Rule (UCMR 6) for Public Water Systems
The EPA is rolling out the sixth Unregulated Contaminant Monitoring Rule (UCMR 6) to check for new, sneaky chemicals in public drinking water. Big water systems serving 3,300+ people and some smaller ones will test for 30 different contaminants, including certain PFAS and pesticides, to keep our water safe. Comments and feedback are open until late August 2026, and the EPA will host fun online meetings to chat about the plan!
Previous / Next Documents
Previous: 2026-12542, Naturalization Application Fee Adjustments
The Department of Homeland Security wants to change the fees for applying to become a U.S. citizen. They plan to remove the lower fee and fee waivers for most people, but military members still won’t have to pay. If you want to share your thoughts, you have until August 24, 2026, to comment before these changes might take effect.
Next: 2026-12551, Approval and Promulgation of Implementation Plans; Arizona; Revisions to the Cleaner Burning Gasoline, Winter Oxygenated Fuel, and Gasoline Set-Aside Programs
The EPA wants to approve Arizona’s updates to cleaner gasoline and winter fuel rules that help cut pollution in Phoenix and Tucson. They’re also getting rid of an old gasoline program in parts of Maricopa and Pima counties. These changes won’t cost extra or add new rules, and folks have until July 23, 2026, to share their thoughts.