Major U.S. Environmental Laws

The big picture: one law per problem

Environmental laws are tools. Each one targets a specific problem and uses a specific method. On the AP® Environmental Science exam, you are often asked to match a law to a problem, explain how it works, or evaluate how well it works.

The Environmental Protection Agency (EPA) writes and enforces the detailed rules that carry out these laws. Congress passes the law; the EPA turns it into standards, permits, and penalties. States often run the programs, with the EPA overseeing them.

The Clean Air Act

The Clean Air Act (1970, major amendments in 1990) directs the EPA to protect air quality and public health.

Method 1: National Ambient Air Quality Standards (NAAQS). The EPA sets maximum allowed concentrations for six criteria pollutants:

• carbon monoxide (CO)

• lead (Pb)

• nitrogen dioxide (NO₂)

• sulfur dioxide (SO₂)

• ground-level ozone (O₃)

• particulate matter (PM)

Each state monitors its air. A county that does not meet a standard is called a nonattainment area, and its state must write a plan to clean up the air, such as stricter limits on factories or vehicle inspections. This is how standards lead to cleaner air in cities: the standard is a target, and failing to meet it triggers required action.

Method 2: Emission limits and technology. The law also limits what vehicles and power plants may emit. Catalytic converters on cars and the phaseout of leaded gasoline come from this law.

Method 3: Cap-and-trade (1990 amendments). To fight acid rain, the law capped total SO₂ emissions from power plants.

Evaluation. Cap-and-trade was very effective at cutting SO₂ and reducing acid rain, and it cost less than predicted. Limitations: it does not stop local pollution hot spots (a plant that buys allowances can still pollute heavily near one town), and the cap must be set strictly enough to matter. Compare this with a technology mandate (every plant must install the same scrubber): a mandate is simple and predictable, but it gives no reward for finding cheaper or better ways to cut emissions, and it costs more overall.

The Clean Water Act

The Clean Water Act (1972) aims to make surface waters (rivers, lakes, coastal waters) safe for fishing and swimming and to stop pollution at its source.

Point sources. A point source is a single identifiable place where pollution enters water, such as a pipe from a factory or a sewage treatment plant. Under the Act, it is illegal to discharge pollutants from a point source without a permit (the NPDES permit). A permit is legal permission that sets limits on what, and how much, a facility may release, along with required monitoring and reporting. Breaking the permit leads to fines.

Nonpoint sources. Nonpoint source pollution comes from many scattered places, such as fertilizer and pesticide runoff from farms, oil washed off streets, and lawn chemicals. There is no single pipe to attach a permit to, so it is much harder to measure, trace, and regulate. Solutions rely more on management practices (buffer strips, cover crops, reducing fertilizer) than on permits.

The Endangered Species Act

The Endangered Species Act (ESA, 1973) protects species at risk of extinction and the ecosystems they depend on.

• Endangered: in danger of extinction across all or most of its range.

• Threatened: likely to become endangered in the foreseeable future.

Once a species is listed, it is illegal to kill, harm, or collect it, and the government may designate critical habitat, areas essential to its survival. Federal agencies must check that their projects (like highways or dams) do not jeopardize listed species. Recovery plans then guide efforts to rebuild populations until the species can be removed from the list ("delisted").

Criticism. Landowners sometimes argue that protecting a listed species' habitat limits how they can use their land (farming, logging, building), costing them income without compensation. Supporters respond that biodiversity provides ecosystem services and that incentives and agreements can reduce the burden.

Cleaning up and preventing: CERCLA and RCRA

Think of these two laws as a pair: one fixes old messes, the other prevents new ones.

CERCLA (1980), the "Superfund" law. The Comprehensive Environmental Response, Compensation, and Liability Act deals with abandoned or uncontrolled hazardous waste sites, like Love Canal in New York. The EPA ranks the worst sites on the National Priorities List. Key idea: liability. The law can require potentially responsible parties (PRPs) to pay for cleanup: current and past owners, operators, and companies that generated or transported the waste. This is "the polluter pays." When no responsible party can be found or can pay (for example, the company went bankrupt), the Superfund trust fund can pay for cleanup, and the EPA may try to recover costs later.

RCRA (1976). The Resource Conservation and Recovery Act regulates solid and hazardous waste from the start. Its central idea is "cradle-to-grave" management: hazardous waste is tracked from where it is generated, through transport, to its final treatment, storage, or disposal, with paperwork (a manifest) at each step. It also sets rules for landfills (liners, leachate collection) and encourages waste reduction and recycling.

Evaluating the two together.

Back to the start: the burning Cuyahoga River pushed Congress to pass laws that match each problem with a method: permits for pipes, standards for air, protection for species, liability for old sites, and tracking for waste.

Summary