US cities join lawsuits against EPA over power plant emissions rollback

A coalition of US cities, including Chicago, Denver and New York City, has joined multistate lawsuits challenging the Environmental Protection Agency’s decision to end greenhouse gas emissions standards for power plants and its failure to enforce requirements on existing gas-fired facilities.

The legal action, filed in early October 2026, represents a direct confrontation between municipal governments and the federal agency over climate policy. The lawsuits argue that the EPA’s rollback violates the Clean Air Act and undermines years of progress in reducing carbon emissions from the US power sector.

Power plants remain the second-largest source of greenhouse gas emissions in the United States, behind transportation. The EPA’s move to scrap emissions standards for new plants and decline to regulate existing gas-fired facilities has drawn sharp criticism from environmental groups, public health advocates and city officials who say local communities will bear the brunt of increased air pollution.

The legal challenge

The lawsuits, filed in multiple federal courts, bring together state attorneys general and city legal departments. Chicago, Denver and New York City have filed amicus briefs or joined as co-plaintiffs, arguing that the EPA’s action directly harms their residents and undermines local climate commitments.

New York City has pledged to reduce citywide emissions 80 percent by 2050 compared to 2005 levels. Denver’s climate action plan targets a 100 percent renewable electricity grid by 2030. Chicago’s 2022 climate action plan aims for carbon neutrality by 2050. All three cities say the EPA rollback makes these targets harder to achieve because power plant emissions outside city boundaries still contribute to local air quality problems.

The legal arguments centre on two main points. First, the EPA’s decision to end emissions standards for new power plants is procedurally flawed and fails to consider the agency’s own finding that greenhouse gases endanger public health and welfare. Second, the agency’s refusal to set emissions guidelines for existing gas-fired plants violates the Clean Air Act’s requirement that the EPA regulate stationary sources that contribute to air pollution.

What the rollback changes

The EPA’s action, announced in September 2026, rescinds the 2015 Clean Power Plan and subsequent replacement rules that set carbon emissions limits for new and existing power plants. The agency said the regulations imposed excessive costs on the energy sector and exceeded the EPA’s statutory authority under the Clean Air Act.

Under the rollback, new coal and gas-fired power plants will not be required to install carbon capture technology or meet specific emissions limits. Existing gas-fired plants, which now generate about 40 percent of US electricity, face no new federal emissions requirements. The EPA also withdrew proposed guidelines for reducing methane emissions from existing oil and gas infrastructure.

Environmental analysts estimate the rollback could add between 200 million and 400 million metric tons of carbon dioxide annually to US emissions by 2030, depending on how many new gas plants are built. That is equivalent to adding 40 to 80 million passenger vehicles to the road each year.

City-level consequences

For cities, the rollback creates a regulatory vacuum that local governments say they cannot fill alone. While cities can regulate emissions from buildings, transport and waste within their boundaries, they have no authority over power plant emissions outside city limits.

Chicago, Denver and New York City have all adopted ambitious climate action plans that rely in part on cleaner electricity from the grid. If power plant emissions rise, those cities will struggle to meet their targets even if they cut local emissions to zero.

Key facts

Broader context

The lawsuits are the latest chapter in a long-running legal battle over federal climate authority. The Clean Power Plan, first proposed in 2015, was never fully implemented. It was stayed by the Supreme Court in 2016, replaced by the Affordable Clean Energy rule in 2019, and that rule was struck down by the DC Circuit Court in 2021. The Inflation Reduction Act of 2022 provided tax credits for clean energy but did not mandate emissions cuts from existing power plants.

The current EPA leadership argues that the Clean Air Act does not give the agency authority to set emissions standards that would force a shift away from fossil fuels. The suing cities and states argue that the endangerment finding, which the EPA has not withdrawn, requires the agency to regulate greenhouse gases from stationary sources.

A ruling in the case could take months or years. In the meantime, the EPA is expected to continue processing permits for new gas-fired power plants without emissions conditions. Several major gas plant projects are in advanced planning stages in the Midwest and Southeast, including facilities that would supply electricity to cities in the suing coalition.

What comes next

The lawsuits will be consolidated in either the DC Circuit Court of Appeals or a federal district court. Oral arguments are unlikely before mid-2027. The cities involved have said they will continue to pursue their own climate policies regardless of the outcome, but acknowledge that federal action is necessary to achieve economy-wide emissions reductions.

For London readers and urbanism professionals, the case highlights a recurring tension in climate governance: cities set ambitious targets, but their ability to meet them depends on policy decisions made at national level. The same dynamic plays out in the UK, where local authorities have declared climate emergencies but have limited control over the national grid’s fuel mix.

Source: Smart Cities Dive – Cities, states sue EPA over power plant emissions rollback (https://www.smartcitiesdive.com/news/cities-states-sue-epa-over-power-plant-emissions-rollback/832011/)