January 10, 2026 - U.S. Environmental Protection Agency (EPA) is finalizing the full disapproval of Colorado’s revised 2022 Regional Haze State Implementation Plan (SIP), preventing the premature closure of power plants. EPA determined that Colorado’s proposal to shut down coal fired power plants, without consent from all of the plants, does not comply with the Clean Air Act (CAA). These plants are vital to delivering reliable and affordable energy to Colorado families. Shutting down these power plants is not necessary to meet Regional Haze requirements, and including forced closure deadlines for facilities that want to stay open would have been a misuse of the CAA. Today’s final action reflects EPA’s commitment to fulfilling all statutory obligations and ensuring Coloradans have affordable baseload power while meeting CAA visibility obligations in Colorado’s national parks and wilderness areas. EPA Administrator Lee Zeldin’s Powering the Great American Comeback initiative prioritizes cooperative federalism, and the agency actively looks for ways to work with states to achieve measured results. EPA stands ready to assist Colorado in creating a regional haze plan that fulfills all statutory requirements. 

“Reliable baseload energy sources are essential to Powering the Great American Comeback and ensuring families have cost-effective energy. The Trump EPA has repeatedly demonstrated that we can achieve our statutory obligations, support baseload power, and improve visibility within our national parks. This is what the American people voted for,” said EPA Administrator Zeldin. “EPA is ready and willing to work full-heartedly with Colorado to revise its SIP, ensuring full compliance with the Clean Air Act as written.”   

“Administrator Zeldin and the Trump Administration are laser focused on ensuring Americans have an abundance of highly reliable and affordable energy,” said EPA Regional Administrator Cyrus Western. “EPA’s denial of Colorado’s SIP revision delivers this outcome in a manner that’s fully compliant with the Clean Air Act while simultaneously providing for clean air for all Americans.” 

Section 110 of the CAA requires states to provide necessary assurances that provisions within SIPs, such as the inclusion of an enforceable closure deadline, are not prohibited under federal or state law. However, Colorado did not provide the required necessary assurances when submitting its SIP. Specifically, the state did not properly consider and explain whether the nonconsensual closure of Colorado Springs Utilities’ Nixon Unit 1 power plant would be an act of taking private property without compensation. The Trump EPA is unequivocally committed to following the CAA and EPA legally cannot approve Colorado’s SIP revision.

Additionally, EPA has concerns that, if approved, Colorado's SIP would harm grid reliability. Years after submitting this SIP revision, and after EPA proposed action on the submission, Colorado withdrew another closure deadline for Comanche Unit 1 after realizing changing circumstances on the ground required additional power supply. This concern is also echoed by the fact that the Department of Energy issued an emergency order on December 30, 2025, under section 202(c) of the Federal Power Act, requiring Craig Station Unit 1 coal power plant in Craig, Colorado, to remain operating due to grid reliability concerns. Coal fired power plants are essential sources of baseload power necessary for addressing surging energy demand, increases in American manufacturing, national security interests, and turning the United States into the Artificial Intelligence capital of the world. Ensuring affordable and reliable energy supplies is a top priority of the Trump Administration. Under Administrator Zeldin’s leadership, EPA has worked tirelessly to fulfill President Trump’s executive orders that promote energy dominance. As EPA delivers on the president’s agenda, finding a path forward that provides reliable energy for Colorado families and businesses remains a priority.

Colorado is now required to submit a revised, approvable SIP, or EPA will need to complete a federal implementation plan (FIP), either of which must be done within two years. The FIP or SIP will need to fully address statutory requirements, including revisions to Colorado’s long-term strategy. The line of communication between Colorado and EPA is open, and the agency looks forward to working hand in hand with Colorado to accomplish a revised SIP.

To read EPA’s full final action disapproving Colorado's SIP revision, please click here.

Background

On July 16, 2025, EPA proposed a partial approval and partial disapproval of Colorado’s regional haze second planning period SIP revision and took public comment on the proposed action for 60-days.

The CAA and Regional Haze Rule (RHR) require states, in coordination with EPA and other federal partners, to develop and implement plans to improve visibility impairment in national parks and wilderness areas. Historically, the implementation of this program has imposed significant costs on power plants and other sectors, calling into question the supply of affordable and reliable energy for American families. After years of implementation and feedback from stakeholders, it is clear that the Regional Haze program is broken and needs significant revisions to clarify requirements and alleviate the unnecessary burdens on states and the regulated community, and more closely align with Congressional intent.

On December 31, 2025, Administrator Zeldin signed a final rule revising the current RHR to extend the due date from July 31, 2028, to July 31, 2031, for the third planning period of SIPs. EPA is extending this deadline to ensure that states and regional planning organizations have adequate time to adapt third planning period SIPs to any changes EPA makes to the RHR as part of the ongoing effort to restructure existing regulations. This action was first announced through an Advanced Notice of Proposed Rulemaking. This final rule does not impact EPA’s decision on Colorado’s SIP revision for the second planning period, as the second period required SIP revisions by 2021.