The National Environmental Policy Act (NEPA) is a U.S. law passed in 1970 to help protect and improve the environment. It requires federal government agencies to examine how their actions might affect the environment. NEPA also created the President's Council on Environmental Quality (CEQ). The law was approved by the U.S. Congress in December 1969 and signed by President Richard Nixon on January 1, 1970. More than 100 countries have created similar laws based on NEPA.
NEPA asks federal agencies to study the possible effects of their actions on the environment. The most important part of NEPA is the rule that all federal agencies must prepare environmental assessments (EAs) and environmental impact statements (EISs). These reports describe the possible environmental effects of planned actions. The U.S. Congress believes everyone has a duty to protect and improve the environment for future generations. NEPA's rules do not apply to the president, Congress, or federal courts because they are not considered "federal agencies." However, if a federal agency acts based on an order from the president, that action may still need to follow NEPA's requirements.
History
The National Environmental Policy Act (NEPA) was created because people became more aware of and worried about the environment in the 1960s. During this time, the United States saw more factories, more cities and suburbs, and more pollution. Environmental groups and the public, inspired by Rachel Carson’s 1962 book Silent Spring, supported laws like the 1964 Wilderness Act, the 1970 Clean Air Act, and the 1972 Clean Water Act. In 1969, public anger over the Santa Barbara oil spill happened just as lawmakers were writing NEPA. A fire on the Cuyahoga River, reported in Time magazine after a Senate vote, also drew attention. Another reason for NEPA was the 1960s highway revolts, when people protested the destruction of communities and nature during the building of highways. Indiana political scientist Lynton Caldwell also showed that concern about careless international development projects in the 1950s and 1960s influenced NEPA’s creation.
In 2015, a U.S. District Court explained that by the late 1960s, people realized that America’s progress had harmed the environment. A congressional investigation found that the federal government had mismanaged natural resources. Because of this, lawmakers and the public demanded stronger environmental protection. Congress responded by passing NEPA in 1970, which became the nation’s main law for protecting the environment. NEPA required federal agencies to carefully study the environmental effects of their actions and take steps to avoid harm. It also added rules to rebuild trust in the government by making agencies follow specific steps before starting projects.
Since NEPA was passed, it has applied to any major project, whether run by the federal, state, or local government, that uses federal money, involves federal work, or needs a permit from a federal agency. Courts later expanded this to include projects that require a federal permit, even if they are fully funded by private companies. This is because getting a federal permit usually involves federal employees or contractors, which means federal resources are used, even if no direct money is spent.
A U.S. District Court also said that even the President must review NEPA analysis before making decisions about major projects.
Contents
The introduction to NEPA states:
NEPA has three parts. The first part explains national environmental policies and goals. The second part describes how federal agencies must follow these policies and goals. The third part creates the Council on Environmental Quality (CEQ) within the Executive Office of the President.
The goal of NEPA is to make sure that environmental concerns are considered equally with other factors when federal agencies make decisions. It also creates a national environmental policy. NEPA requires the CEQ to help the President prepare an annual report about how well federal agencies follow NEPA. The CEQ also advises the President on environmental policy and the condition of the environment.
NEPA sets this national environmental policy by requiring federal agencies to prepare an environmental impact statement (EIS) for reports and recommendations that ask Congress for funding. NEPA is a law that requires action but does not include criminal or civil penalties. This means that NEPA must be enforced through the court system. In practice, a project must follow NEPA guidelines if a federal agency provides any financial support for the project. However, if a federal employee reviews a project, this action may require an analysis that follows NEPA rules.
NEPA applies to many actions taken by federal agencies. However, it does not apply to actions taken by states if there is no federal involvement or funding. NEPA also includes exemptions and exceptions, such as specific federal projects described in laws and exemptions for the Environmental Protection Agency (EPA). Exemptions also apply when other environmental laws require a similar impact analysis. These laws include, but are not limited to, the Clean Air Act, Resource Conservation and Recovery Act, Safe Drinking Water Act, and the Federal Insecticide, Fungicide, and Rodenticide Act.
Process
The National Environmental Policy Act (NEPA) process is used to study the environmental effects of federal projects or actions required by NEPA. This process starts when a government agency creates a plan to address a need. If the action is covered by NEPA, the agency must complete three steps to follow the law. These steps include preparing a Categorical Exclusion (CatEx), an environmental assessment (EA), and either a Finding of No Significant Impact (FONSI) or an environmental impact statement (EIS).
Executive Order No. 11514 (March 5, 1970; Nixon administration) and Executive Order No. 11991 (May 24, 1977; Carter administration) require the Council on Environmental Quality (CEQ) to create rules for federal agencies to follow NEPA. These rules must be followed by all agencies. The Supreme Court of the United States says that CEQ rules are given great respect. CEQ’s NEPA regulation, 40 C.F.R. § 1501.4, explains how to decide whether to prepare an Environmental Impact Statement (EIS).
Federal agencies must also follow rules in 40 C.F.R. § 1500 through § 1508 and create additional rules for their own NEPA work. For example, the Federal Highway Administration’s rules are in 23 C.F.R. § 771.101 through § 771.131. According to 23 C.F.R. § 771.115(a), Class I actions, such as building a new highway with four or more lanes, have major environmental effects and require an EIS. According to 23 C.F.R. § 771.115(b) and § 771.117(c), Class II actions, such as adding bike lanes or planting trees, usually do not cause major environmental effects and may be exempt unless unusual conditions apply, as stated in 23 C.F.R. § 771.117(b). According to 23 C.F.R. § 771.117(c), all other actions are Class III and require an EA to decide what environmental document is needed.
A Categorical Exclusion (CatEx) is a list of actions an agency has decided do not cause major environmental effects (40 C.F.R. § 1508.4). If a proposed action is on an agency’s CatEx, the agency must check for unusual conditions, such as effects on endangered species, protected cultural sites, or wetlands. If the action is not on the CatEx, an EA must be prepared. If similar actions were found to have no environmental effects in past EAs, an agency may update its CatEx rules. These changes are published in the Federal Register, and the public must be allowed to comment. An agency cannot use another agency’s CatEx to avoid preparing an EA or EIS for its own action, but it may use that agency’s experience to support its own CatEx.
The CEQ created CatEx to reduce paperwork (40 C.F.R. § 1500.4(p)) and delays (40 C.F.R. § 1500.5(k)) so agencies can focus on actions with major environmental effects. In 2003, the National Environmental Policy Task Force found that agencies had confusion about how to use CatEx. In 2010, the CEQ updated its guidance for CatEx, noting that agencies have used CatEx more often since the 1970s. The guidance warns that improper use of CatEx can harm NEPA’s goals by reducing environmental analysis and public input, which may increase legal challenges. The CEQ says CatEx must cover the full proposed action, not just parts of it. Examples of unusual conditions that prevent using CatEx include effects on protected species, habitats, or historic sites. The CEQ cited the 2010 Deepwater Horizon oil spill as a reason agencies should review their CatEx regularly for new environmental risks.
Some people criticize using CatEx to speed up NEPA, such as when BP’s exploration plan for the Deepwater Horizon oil spill used a CatEx instead of an EIS.
An EA is a short public document that explains the need for a proposal, lists alternatives, and names agencies and people involved in drafting the proposal. The purpose of an EA is to determine whether the proposal has major environmental effects and to examine alternatives for achieving the agency’s goals. An EA provides enough information to decide if an EIS is needed, helps agencies follow NEPA when an EIS is not required, and supports preparing an EIS when needed.
Most agency rules do not require public input before finalizing an EA, but agencies often allow public comments during the draft EA stage. An EA must be long enough to support a decision about whether to prepare an EIS but should not replace an EIS.
The CEQ regulation, 40 C.F.R. § 1500.1(b), says: “NEPA procedures must ensure that environmental information is available to public officials and citizens before decisions are made and before actions are taken.” Also, 40 C.F.R. § 1500.2 says: “Federal agencies shall, to the fullest extent possible, encourage and facilitate public involvement in decisions that affect the quality of the human environment.” A U.S. District Court says that public input on a draft EA is essential.
If no major environmental effects are found after studying the proposal and preparing an EA, the agency must write a Finding of No Significant Impact (FONSI). This document explains why the action will not have major environmental effects and includes the EA or a summary of the EA that supports the FONSI decision.
If it is determined that a proposed federal action does not fall within…
Mootness doctrine used to evade NEPA requirements
The Administrative Procedure Act at 5 U.S.C. § 702 allows a person who has been harmed by a NEPA issue to take legal action in court. Under 5 U.S.C. § 706, the U.S. Congress gives courts the power to issue fair solutions, such as an injunction, to force an agency to act or to stop actions that are unreasonable, based on poor judgment, or not in line with the law. However, a court case becomes moot (no longer active) when there are no real issues left, as explained in Powell v. McCormack, 395 U.S. 486 (1969), pages 496–497.
In early NEPA cases, such as Arlington Coalition on Transportation v. Volpe, 458 F.2d 1323 (4th Cir. 1972), page 1331, courts said projects were not within their reach (moot) if the project had advanced to a point where changing it would cost more than the benefits. However, by 1981, the Ninth Circuit Court of Appeals noted that some projects might begin construction to avoid NEPA requirements. The court warned that even completed projects could be ordered to be removed, as stated in Columbia Basin Land Protection Assoc. v. Schlesinger, 643 F.2d 585 (9th Cir. 1981), page 591, note 1.
Courts have the power to stop projects that are built in bad faith to avoid NEPA rules. However, even if a court recognizes this tactic, it may not order the removal of construction or environmental cleanup unless the NEPA complaint specifically asks for these actions as a "live" issue, as noted in the dissenting opinion in West v. Secretary of Dept. of Transp., 206 F.3d 920 (9th Cir. 2000), page 931.
If a NEPA complaint only asks to stop construction, then construction cannot be stopped after it is completed. In Sierra Club v. Marsh, 872 F.2d 497 (1st Cir. 1989), page 500, the First Circuit Court of Appeals stated that harm in NEPA cases refers to harm to the environment. The court also noted in Sierra Club v. Marsh, page 504, that it is appropriate to issue preliminary injunctions early in NEPA cases to prevent harm.
To have standing in a federal court case, at least one individual plaintiff must show that they have been injured by the defendant and that this injury could be fixed by a court decision, as explained in Lujan v. Defenders of Wildlife, 504 U.S. 555, 112 S. Ct. 2130, 119 L. Ed. 2d 351 (1992), pages 560–561.
To have a "live" issue after a project is completed, at least one person must prove that they will personally suffer harm from the project and that this harm could be fixed by removing the project, as stated in Columbia Basin Land Protection Assoc. v. Schlesinger. Individual injuries in NEPA cases often involve environmental effects like air, noise, and water pollution, safety concerns, and long-term impacts. These are discussed in Coalition for Canyon Preservation v. Bowers, 632 F.2d 774 (9th Cir. 1980). Proving individual harm prevents a court from dismissing a case due to a "generalized grievance," as noted in Juliana v. US, 217 F. Supp. 3d 1224 (D. Or. 2016).
Federal courts decide if they have the authority to hear a case (jurisdiction) based only on the parts of a complaint that address the federal issue. This is called the "well-pleaded" complaint rule. If a complaint requests the removal of construction that has not yet started, federal courts may ignore that part because the construction was not an actual controversy at the time the complaint was filed. If construction begins after a NEPA complaint is filed, the complaint may need to be updated or a new complaint filed to include the actual construction. Otherwise, after construction is completed, a federal court may find it no longer has authority (jurisdiction) to decide the case, making it moot.
Courts weigh the harm an injunction might cause to the defendant against the likelihood of environmental harm and the severity of that harm if it occurs. The U.S. Supreme Court explained that environmental harm is often irreversible in Amoco Production Co. v. Gambell, 480 U.S. 531, 107 S. Ct. 1396, 94 L. Ed. 2d 542 (1987), page 545.
Courts may not consider harm caused by the defendant if construction began before the environmental issues were resolved, as noted in Davis v. Mineta, 302 F.3d 1104 (10th Cir. 2002), page 1116.
In Columbia Basin Land Protection Assoc. v. Schlesinger, it was stated that allowing construction to make NEPA cases moot goes against the intent of the U.S. Congress. To prevent NEPA cases from becoming moot due to construction, NEPA complaints must request the removal of projects built in bad faith.
Council on Environmental Quality
The Council on Environmental Quality (CEQ) was based on the Council of Economic Advisers, a group in the executive branch created by the Employment Act of 1946 to help the President with economic issues. After the CEQ was created by the National Environmental Policy Act (NEPA), President Richard Nixon expanded its responsibilities through Executive Order 11514. He told the CEQ to create guidelines for preparing an Environmental Impact Statement (EIS) and to organize and manage federal programs related to environmental quality. The CEQ is part of the Executive Office of the President of the United States. It has three members chosen by the President and later approved by the Senate.
The CEQ has played an important role in developing the EIS process. Its first guidelines, issued in 1971, required every federal department and agency to create their own rules that matched the CEQ’s guidelines. These guidelines were not official regulations, but they were often treated as if they were in court cases. In 1977, President Jimmy Carter used Executive Order 11991 to allow the CEQ to create official regulations instead of just guidelines for preparing EISs. However, the CEQ still did not have the power to enforce these regulations.
In recent years, the CEQ has created advisory documents explaining the general structure of NEPA and the idea of cumulative impacts, among other topics. The CEQ also runs a website called the Citizen's Guide to NEPA as part of its duties. CEQ regulations require federal agencies and other groups to include NEPA requirements in planning processes as early as possible. This ensures that decisions consider environmental values and prevents delays or conflicts that might happen if these requirements are added later. Section 102(2)(C) of NEPA, which is a rule that requires action, states that every recommendation or report on proposals for legislation and other major federal actions that greatly affect the environment must include a detailed statement from the responsible official about the environmental impact of the proposed action. This statement must include all the information needed for an EIS.
Consequences for violating the National Environmental Policy Act
Agencies that break the rules of NEPA may damage their reputation, which can make it harder for them to get money in the future. The CEQ does not have the power to enforce its guidelines, so claims of violations usually go to court. These lawsuits can cost the federal government money and use resources, and they can also delay projects for many years. Some large projects have been stopped or canceled because of these delays, such as the planned Keystone XL Pipeline. The expansion of this project was stopped by TC Energy in 2021 after delays, including when a court rejected its NEPA review in the case Indigenous Environmental Network v. U.S. Department of State. Most often, courts require agencies to redo the environmental review or report that was found to be incomplete.
National Environmental Policy Act and environmental justice
The National Environmental Policy Act (NEPA) can influence environmental justice in different ways. It helps promote fairness by requiring federal agencies to include minority and low-income communities in their environmental studies. Executive Order #12898 (Feb. 11, 1994; Clinton administration) asks federal agencies to examine how proposed actions affect human health, as well as economic and social conditions, especially for minority and low-income populations, who are often more affected by environmental harm. Any new federal plans must consider "serious and harmful environmental effects" on these groups.
NEPA can also create challenges for environmental justice. In New York, a plan to reduce traffic congestion was expected to improve air quality and public transportation. However, it took four years to complete a lengthy environmental review for the NEPA process, and the project faced delays due to lawsuits claiming the review was incomplete. A wind energy project on Cape Cod was stopped after 16 years of legal disputes related to NEPA. Some power lines needed to support clean energy projects were canceled because of NEPA-related lawsuits, as were the Calico Solar project in the Mojave Desert.
Recent developments
On August 15, 2017, President Donald Trump issued Executive Order (E.O.) 13807, titled "Establishing Discipline and Accountability in the Environmental Review and Permitting Process for Infrastructure Projects." This order instructed the Council on Environmental Quality (CEQ) to use its authority to interpret the National Environmental Policy Act (NEPA) in a way that would make the NEPA review process faster and simpler. It also required government agencies to create rules for regularly reviewing and updating "categorical exclusions," which are categories of projects that do not need full environmental reviews. The order canceled President Obama's Executive Order 13690, which included climate science in flood risk management policies.
In July 2020, the Trump administration's CEQ introduced a final rule that weakened NEPA by limiting the time agencies could use to prepare Environmental Assessments (EAs) to one year and Environmental Impact Statements (EISs) to two years. The rule also removed some projects from needing environmental reviews and stopped agencies from considering the combined effects of multiple projects, including those linked to climate change. Later, the Biden administration's CEQ made two changes to bring back rules that were in place before the first Trump administration: the Phase 1 Final Rule (April 20, 2022) and the Phase 2 Final Rule (May 1, 2024).
In 2025, the second Trump administration asked the CEQ to cancel all rules it had created to implement NEPA since 1977. Supporters of this move said it would make the permitting process faster. However, environmental and animal welfare groups argued that it would limit the public’s ability to raise concerns about harm to wildlife habitats, biodiversity loss, and declines in air and water quality.
A legal case about the Uinta Basin Rail project, which would transport crude oil from wells to ports and refineries, led to a Supreme Court hearing about NEPA. This followed a lower court ruling that opposed the rail project. On May 29, 2025, the Supreme Court ruled 8 to 0 (with one judge not participating) that the lower court had misunderstood NEPA. Justice Brett Kavanaugh explained that NEPA’s purpose is to require agencies to prepare an EIS as a procedural step. Justice Sonia Sotomayor agreed with the ruling and noted that the Surface Transportation Board would not be held responsible for harms caused by the oil industry. A law professor, Richard Lazarus, said the court’s decision changed the way NEPA has been interpreted for 50 years.
Analysis of effects
There is not enough information about the costs and benefits of NEPA. A 2025 review found that environmental reviews have taken much longer in recent years, and some infrastructure costs have risen since NEPA was passed. However, it is unclear if NEPA directly caused these increases. On the benefits side, some examples show that NEPA has helped reduce some of the biggest problems, but there is not enough organized information to fully understand its benefits.