The Environmental Protection Agency is the federal agency responsible for protecting human health and the environment through science-based regulations and enforcement. Established in 1970 amid growing public concern over pollution and a series of human-made environmental disasters, the EPA has since played a central role in dramatically reducing air, water, and land pollution across the United States.
Hours of research by our editors, distilled into minutes of clarity.
The EPA spent $13.7B in 2024, making it 23rd among federal agencies in total expenditures. Of that money, more than half was distributed to state environmental agencies for sustainability and environmental protection programs.
Disasters such as the Cuyahoga River fire and the Santa Barbara oil spill prompted Congress and President Nixon to establish the Environmental Protection Agency in December 1970, with the goal of unifying federal efforts to control pollution.
In the 1950s, chemist Arie Haagen-Smit applied methods he'd used studying pineapple plant chemistry to smog-filled air—discovering that sunlight reacting with car exhaust produced photochemical smog from hydrocarbons and nitrogen oxides, not factory smoke.
The hazy phenomenon's name is a combination of "smoke" and "fog" and is composed of chemical pollutants that can cause eye irritation, lung damage and harm to crops. Smog buildup is more common in cities with sunny climates, minimal wind and surrounding mountains that trap these chemicals.
During the 1970s, Democrats and Republicans alike backed landmark environmental laws. Congress passed the Clean Air, Clean Water, and Endangered Species Acts with overwhelming bipartisan majorities—reflecting broad public agreement on protecting the environment.
Passed in 1970 and strengthened through multiple amendments, the Clean Air Act authorizes the EPA to set national air quality standards, regulate industrial and vehicle emissions, and reduce pollutants such as ozone, sulfur dioxide, and lead.
Enacted in 1972, the Clean Water Act grants the Environmental Protection Agency the authority to regulate pollutant discharges, establish water quality standards, and oversee water pollution controls. Its scope has narrowed due to recent Supreme Court rulings.
Known as Superfund sites, these toxic locations undergo long-term cleanup to remove hazardous waste, protect health, and restore land for safe reuse. As of 2025, the EPA lists around 1,300 active Superfund sites on its National Priorities List, with more than 450 cleaned and removed since 1980.
Passed in 1974, the Safe Drinking Water Act requires the EPA to set and enforce national standards for public water systems. It regulates contaminants, funds infrastructure improvements, and ensures that communities nationwide have access to safe and clean drinking water.
Brownfields are properties where redevelopment is complicated by contamination from past industrial or commercial use. The EPA's Brownfields Program funds cleanup and reuse of these sites, transforming abandoned lots into housing, parks, and businesses while boosting local economies.
Since our ancient human relatives began using stone tools to perform tasks, humans have harnessed scientific knowledge and new technologies to expand the boundaries of our understanding of the natural world. From quantum computing and microplastics to artificial intelligence and memory, explore these topics and more with our concise yet informative overviews and expert-curated resources.