The Environmental Protection Agency EPA

At the end of the 1960s rivers were catching fire, smog was killing people in its worst episodes, and pollution control was scattered across a dozen federal offices with no single owner. Richard Nixon proposed a new agency by Reorganization Plan No. 3 of 1970, and the Environmental Protection Agency opened on December 2, 1970, under William Ruckelshaus. Congress then gave it the laws it still enforces: the Clean Air Act amendments of 1970, the Clean Water Act of 1972, the Safe Drinking Water Act, the pesticide and toxic substances laws, the hazardous waste law, and in 1980 the Superfund program for cleaning up contaminated sites.

The EPA works mostly by setting national standards that states then implement and enforce under federal oversight, a model called cooperative federalism. It sets limits on air pollutants and emissions from power plants, factories, and vehicles. It issues permits for discharges into rivers and lakes, sets drinking water standards, registers pesticides before they can be sold, reviews new chemicals, and tracks toxic releases. It directs the cleanup of more than 1,300 Superfund sites and distributes billions in grants for water and sewer systems. Ten regional offices handle most day-to-day work with the states.

Before 2025 the agency employed about 16,000 people on a budget near 9 billion dollars. Its Administrator is confirmed by the Senate and, though EPA is not a cabinet department, has held cabinet-level status in most recent administrations. Air quality has improved dramatically since 1970: emissions of the six common air pollutants have fallen by roughly three quarters even as the economy grew several times over. Supporters credit regulation, while critics argue the later rules cost more than they deliver.

The agency's authority over greenhouse gases has been the central legal fight for two decades. The Supreme Court held in 2007 that carbon dioxide is an air pollutant under the Clean Air Act, and the EPA's 2009 endangerment finding became the basis for vehicle and power plant rules, which the Court narrowed in West Virginia v. EPA in 2022. In 2025 the agency moved to rescind the endangerment finding, rolled back dozens of rules, eliminated its research office, and cut staff substantially. Its leadership argued the changes would lower costs and restore limits on its authority. Environmental and public health groups, along with several states, sued to stop them. On February 12, 2026, the EPA finalized the repeal of the 2009 endangerment finding along with all federal greenhouse gas standards for motor vehicles, and states and health and environmental groups challenged the repeal in the D.C. Circuit.