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

In 1970, in response to the welter of confusing, often ineffective environmental protection laws enacted by states andcommunities, Pres.Richard Nixon created the EPA to fix national guidelines and to monitor and enforce them. Functions of three federal departments—of theInterior, ofAgriculture, and ofHealth, Education, and Welfare—and of other federal bodies were transferred to the new agency. The EPA was initially charged with the administration of theClean Air Act (1970), enacted to abateair pollution primarily from industries and motor vehicles; theFederal Environmental Pesticide Control Act (1972); and theClean Water Act (1972), regulating municipal and industrial wastewater discharges and offering grants for buildingsewage-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, androdenticides; andasbestos hazards in schools.

One of the EPA’s early successes was an agreement with automobile manufacturers to installcatalytic 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 theUnited States from 1970 to 1990, and during the 1980s the pollution standards index improved by half in major cities; significant improvements in water quality andwaste disposal also occurred. TheComprehensive Environmental Response, Compensation, and Liability Act (also calledSuperfund), 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 remainedformidable for years thereafter.

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 withamendments that called for reductions insulfur dioxide generation and the phasing out of chemicals that deplete theozone layer, and a rule requiring the removal of all remaininglead ingasoline starting in 1996. Other regulations introduced during this time included the Nuclear Waste Policy Act (1982) and theEnergy Star program (1992); the latter wasimplemented to rate the usage costs and energyefficiency ofhousehold appliances and other electronic devices. This period also saw the development of theEmergency 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.

In the early 21st century the EPA’s role expanded to addressclimate change andglobal warming. In 2007 theU.S. Supreme Court ruled in a case brought by the state ofMassachusetts against the EPA that failure to regulategreenhouse 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 ofcarbon dioxide and five other greenhouse gases. Stemming from thismandate, the EPA worked with theU.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. In 2022, however, the U.S. Supreme Court constrained the EPA’s authority in a challenge brought by the state ofWest Virginia, ruling that the EPA could not, without additional authorization from the U.S. Congress, regulate power plants byimposing caps on carbon and other greenhouse-gas emissions that would force industries to shift to cleaner power-generating technologies.