Environmental Groups Sue EPA Over Endangerment Finding Repeal

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A coalition of environmental groups, including the Sierra Club and Union of Concerned Scientists, have filed a lawsuit against the EPA over its repeal of the endangerment finding, which defined greenhouse gases as air pollutants under the Clean Air Act. The EPA is arguing that the Clean Air Act was only intended for local and regional pollution, citing recent Supreme Court rulings that limit agency power without clear congressional authorization.

Why it matters

This legal battle over the EPA's reversal of greenhouse gas regulations could have major implications for the federal government's ability to address climate change. The outcome of the case, which is likely headed to the Supreme Court, will determine the EPA's authority to regulate emissions and set the stage for future environmental policy.

The details

The environmental groups argue the EPA is recycling legal theories already rejected by the 2007 Massachusetts v. EPA ruling, which defined greenhouse gases as air pollutants. However, the EPA contends that the Clean Air Act was only intended to address local and regional pollution, citing recent Supreme Court decisions that limit agency power without clear congressional approval.

• The lawsuit was filed in the DC Circuit on February 18, 2026.
• The case is expected to eventually reach the Supreme Court.

What’s next

The case is expected to eventually reach the Supreme Court, which will make a final ruling on the EPA's authority to regulate greenhouse gas emissions.