The Clean Air Act (1963, major amendments 1970, 1990) is the federal law regulating air pollution from stationary and mobile sources. It authorizes EPA to establish National Ambient Air Quality Standards (NAAQS) to protect public health, requires states to develop implementation plans, and regulates emissions from vehicles, power plants, and factories. Massachusetts v. EPA (2007) held that greenhouse gases are "air pollutants" covered by the Act, requiring EPA to regulate them if they endanger health. The 2026 endangerment finding repeal attempts to circumvent this ruling.
The Clean Air Act is the legal foundation for all federal air pollution regulation, and the 2026 repeal of the endangerment finding threatens all climate regulations built on it. Understanding the law and the legal fight over it is central to understanding climate policy today.
People often think the Clean Air Act only covers smog and visible pollution. It covers greenhouse gases too—the Supreme Court made that clear in Massachusetts v. EPA, and the EPA spent 16 years regulating greenhouse gases under that authority before the 2026 repeal.
The Clean Air Act is the legal foundation for all federal air pollution regulation, and the 2026 repeal of the endangerment finding threatens all climate regulations built on it. Understanding the law and the legal fight over it is central to understanding climate policy today.
People often think the Clean Air Act only covers smog and visible pollution. It covers greenhouse gases too—the Supreme Court made that clear in Massachusetts v. EPA, and the EPA spent 16 years regulating greenhouse gases under that authority before the 2026 repeal.