The Ten Most Important U.S. Environmental Laws

In choosing the top environmental laws, I wanted to focus on those with the largest impacts on the environment, not just those that are most important to environmental lawyers or best known. My own priorities are public health, climate change, and preservation of biodiversity/ecosystems. I included all laws passed in the U.S., not just federal regulatory laws, and some of my selections may not be what you expected.  I’ve listed the laws in chronological order to avoid the need to rank them.

National Environmental Policy Act (NEPA). This law, signed on the first day of 1970, requires agencies to disclose the environmental effects of their actions. This marked the beginning of a decade of legislative environmental legislation. NEPA remains the workhorse of natural resource litigation today.

Clean Air Act.  If I were listing laws in order of importance, I would put the CAA on top. It is significant because if its huge public health benefits and because it has provided the basis for EPA regulation of greenhouse gases.  In public health terms, what makes air pollution distinctive is the millions of people exposes to common pollutants such as particulates and smog. Other substances are more dangerous but the number of people exposed is much smaller.

Clean Water Act.  This law has done a good job at cleaning up municipal and industrial water pollution. Until gutted by the Supreme Court in 2022, it also provided important protection to the nation’s wetlands.

Endangered Species Act (ESA). In some ways the most robust environmental law because of its stringent requirements, which protect rare species and the ecosystems in which they live.

Alaska National Interest Lands Conservation Act (ANILCA). As the largest conservation measures in the nation’s history, ANILCA reserves roughly 65 million acres of land in Alaska from development in national parks, wilderness areas, and other conservation areas.

Comprehensive Emergency Response and Cleanup Act (CERCLA). Provides for cleanup of hazardous waste sites. Also known as the Superfund law. The possibility of CERCLA liability also provides a powerful incentive for voluntary clean-up and for carefully disposing of materials in the first place.

Pavley Act. This California law imposes limits on greenhouse gas emissions from new vehicles, a breakthrough in U.S. climate law. California standards have been adopted by 17 other states plus the District of Columbia.

AB 32. Another California climate law, setting targets for greenhouse gas reductions and providing the basis for California cap and trade system as well as other regulations. Other states have enacted their own climate laws, sometimes building on the California experience.

Inflation Reduction Act. Provides approximately $370 billion dollars for clean energy and other climate-related programs.

Reader’s Choice. To tell the truth, I couldn’t decide on a tenth choice, so I decided to leave it up to you. Among of the possibilities:

• A variety of laws that regulate toxic chemicals (including pesticides) and their disposal, such as RCRA, FIFRA, and TSCA.
• Various laws protecting public lands like the Wilderness Act and the the Antiquities Act,
• Energy laws like the Energy Policy Act of 2005’s provisions for renewables and energy efficiency, or CAFÉ mileage standards,
• Clean Air Act Amendments: the major 1990 Amendments  (especially the acid rain provisions), and recent amendments that apply to super-greenhouse gases.

The choice probably depends on what areas of environmental law you prioritize. Let me know what you pick!