Shannon Silverthorne, ELR Staffer, FLS Class of 2027

On January 9th, 2026, the Environmental Protection Agency (EPA)—in a move that shocked environmental activists—entirely rejected Colorado’s Regional Haze State Implementation Plan (SIP). The Regional Haze SIP was initially submitted to the EPA for a second round of review in 2022. The primary aim of Colorado’s proposed plan was to further bring the state into compliance with the Clean Air Act by closing down certain coal plants in the region, thereby lowering the overall pollutants emitted into the air within the region. 

The EPA, however, took a different stance. In its January 9th rejection of Colorado’s proposal, the EPA asserted that the Regional Haze SIP did not meet the requirements of the Clean Air Act and lacked “necessary assurances that the unconsented source closure [of the coal plant would not result in a taking pursuant to the U.S. Constitution”. Essentially, the state’s plan was rejected due to what the EPA foresaw as an unfavorable economic result for the coal industry.

Environmental groups have primarily criticized the EPA’s January 9th rejection of the state’s proposal as favoring the profitable coal industry over the actual welfare of the state and its people. The senior program manager of the National Parks Conservation Association (NCPA), Tracy Coppola, came forward in a statement to make clear her opinion that the shocking rejection was “dangerous for Colorado’s national parks and for everyone who values clean, healthy air.” 
However, the NCPA isn’t letting the EPA’s decision go unchallenged. They are now fighting back, alleging that the EPA’s rejection of the SIP was an illegal overstep of its powers. On March 4th, 2026, the NPCA filed a petition for review of the January 9th rejection. The state of Colorado itself is also fighting back against the EPA’s rejection of their Regional Haze SIP; Colorado’s Attorney General Phil Weiser, also on March 4th, filed suit against the EPA. Although both petitions are still in their very early stages, it is the hope of both environmental activists and the state of Colorado that their voices will be heard in what they view as an unjust and illegal rejection of the state’s plan to improve overall air quality. Furthermore, it is their goal to ensure that the EPA’s overreach will not be allowed to continue.