Environmental Protection Agency

Environmental Protection Agency (EPA), agency of the U.S. government that sets and enforces national pollution-control standards.

Establishment and early actions

In 1970, in response to the welter of confusing, often ineffective environmental protection laws enacted by states and communities, Pres. Richard Nixon created the EPA to fix national guidelines and to monitor and enforce them. Functions of three federal departments—of the Interior, of Agriculture, and of Health, Education, and Welfare—and of other federal bodies were transferred to the new agency. The EPA was initially charged with the administration of the Clean Air Act (1970), enacted to abate air pollution primarily from industries and motor vehicles; the Federal Environmental Pesticide Control Act (1972); and the Clean Water Act (1972), regulating municipal and industrial wastewater discharges and offering grants for building sewage-treatment facilities. By the mid-1990s the EPA was enforcing 12 major statutes, including laws designed to control uranium mill tailings; ocean dumping; safe drinking water; insecticides, fungicides, and rodenticides; and asbestos hazards in schools.

One of the EPA’s early successes was an agreement with automobile manufacturers to install catalytic converters in cars, thereby reducing emissions of unburned hydrocarbons by 85 percent. The EPA’s enforcement was in large part responsible for a decline of one-third to one-half in most air pollution emissions in the United States from 1970 to 1990, and during the 1980s the pollution standards index improved by half in major cities; significant improvements in water quality and waste disposal also occurred. The Comprehensive Environmental Response, Compensation, and Liability Act (also called Superfund), providing billions of dollars for cleaning up abandoned waste dumps, was first established in 1980, but the number of those waste sites and the difficulties of the cleanups remained formidable for years thereafter.

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Late 20th-century developments

Throughout the 1980s and ’90s the EPA continued to strengthen laws governing air and water quality and toxic substances. However, it also introduced new rules. The EPA’s accomplishments during this period included the requirement that all primary and secondary schools be tested for asbestos starting in 1982, the reauthorization of the Clean Water Act in 1987, the reauthorization of the Clean Air Act in 1990 with amendments that called for reductions in sulfur dioxide generation and the phasing out of chemicals that deplete the ozone layer, and a rule requiring the removal of all remaining lead in gasoline starting in 1996. Other regulations introduced during this time included the Nuclear Waste Policy Act (1982) and the Energy Star program (1992); the latter was implemented to rate the usage costs and energy efficiency of household appliances and other electronic devices. This period also saw the development of the Emergency Planning and Community Right-to-Know Act (EPCRA), which allowed local communities to know the nature of the toxic chemicals produced by industries in their areas and assisted communities in developing emergency plans to deal with hazardous substance releases and exposures.

Early 21st-century developments

In the early 21st century the EPA’s role expanded to address climate change and global warming. In 2007 the U.S. Supreme Court ruled in a case brought by the state of Massachusetts against the EPA that failure to regulate greenhouse gas emissions from motor vehicles was contrary to the requirements of the Clean Air Act. As a result, the EPA was given the responsibility to develop strategies to manage emissions of carbon dioxide and five other greenhouse gases. Stemming from this mandate, colloquially referred to as the “endangerment finding,” the EPA worked with the U.S. Department of Transportation to develop standards that would substantially increase vehicle fuel efficiency, and in 2011 it initiated a permitting program that placed the first limits on greenhouse gas emissions from power plants, refineries, and other large stationary sources (see also What Is the U.S. Environmental Protection Agency’s Endangerment Finding?).

In 2022, however, the U.S. Supreme Court constrained the EPA’s authority in a challenge brought by the state of West Virginia, ruling that the EPA could not, without additional authorization from the U.S. Congress, regulate power plants by imposing caps on carbon and other greenhouse-gas emissions that would force industries to shift to cleaner power-generating technologies. In 2025, during the first week of his second term, Pres. Donald Trump commissioned a review of the endangerment finding, the results of which led to the EPA abandoning the rule in early 2026 and repealing emissions regulations for carbon dioxide and other greenhouse gases for U.S. power plants later that year. The EPA argued that the global effects of greenhouse gas emissions from U.S. cars and trucks did not fall under its purview and that greenhouse gas emissions from U.S. vehicles did not contribute meaningfully to local and regional air pollution, so their effects were too small to constitute a danger to U.S. residents.