NEPA Environmental Review Requirements

The Environmental & Energy Law Program is tracking the environmental regulatory rollbacks of the Trump administration. Click here for the list of rules we are following.

Why It Matters

In 1969, Congress enacted the National Environmental Policy Act (NEPA), which requires federal agencies to assess the environmental impacts of certain proposed actions. It can be thought of as a “look before you leap” law. NEPA quickly became part of the bedrock of U.S. environmental law and a guarantee that the government will consider potential consequences and alternatives before it acts.

Under NEPA, federal agencies must perform an environmental review for each proposed “major federal action.” Major actions include permit decisions, adoption of agency policy, formal planning, agency projects, and other actions. The environmental review process may involve consultation and collaboration with other expert agencies like the Environmental Protection Agency, U.S. Fish and Wildlife Service, and Centers for Disease Control and Prevention. NEPA provides transparency by requiring that draft reviews be publicly disclosed and open for public comment. The final environmental reviews can be challenged in court, allowing for accountability.

NEPA does not require agencies to adopt the least environmentally impactful alternatives when finalizing the project design or eventually taking the action. NEPA provides a process for agencies to follow in decision-making, but does not impose a substantive outcome. The purpose of NEPA is to ensure the agencies make informed decisions, considering a variety of possible alternatives and the environmental consequences. This process allows agencies to analyze their actions thoroughly and see how they might modify projects to prevent harm to the environment and public health while achieving their goals.

There are many instances when the NEPA process has positively shaped agency decisions and actions, leading to more intelligent project designs and better outcomes for people and the environment.

Current Status

During the Trump administration, the White House has revoked guidance issued under the prior administration for how agencies should address greenhouse gases in NEPA evaluations, started a process to revisit NEPA’s implementing regulations, and kicked off individual agency reviews of their internal NEPA regulations and processes. Many agencies have started to review their NEPA processes and have already made changes that affect environmental reviews for projects under their purview. Agencies have even sought to circumvent NEPA entirely. For example, in 2017, the Department of Homeland Security waived NEPA requirements for construction of a 20-mile segment of a border wall and associated infrastructure.

The Department of the Interior is furthest along in its review of internal NEPA procedures. However, other agencies have also taken actions to change or limit the NEPA review process since Trump took office.

Overview of NEPA

There are three types of environmental reviews that may occur for a proposed major federal action: an environmental assessment, an environmental impact statement, or a categorical exclusion.

An environmental assessment (EA) is a preliminary step to determine if the action will significantly affect the quality of the environment. If the agency determines that there will be a significant impact, then it must prepare an environmental impact statement (EIS). An environmental impact statement is an in-depth analysis of the proposed action’s environmental consequences and can take years to finalize. If the agency determines that there will not be a significant impact on the environment, then the agency makes a Finding of No Significant Impact and does not need to prepare an environmental impact statement. These reviews are designed to make an agency consider the environmental consequences of the proposed action, alternative actions the agency could take in lieu of the proposed action, the expected environmental impacts of those alternative actions, and the agency’s rationale for selecting its preferred approach.

Agencies can adopt categorical exclusions which are waivers for categories of certain major federal actions that have been determined not to “individually or cumulatively have a significant effect on the human environment.” If an action falls into a categorical exclusion, no environmental assessment or environmental impact statement is required. Agencies often use categorical exclusions for actions such as routine maintenance, operational activities, and authorization of regularly-occurring actions. An agency’s internal procedures may only require administrative approval to use a categorical exclusion or it may require a documented explanation as to why the proposed action does not require an environmental assessment.

Over time, agencies have attempted to expand the reach of their categorical exclusions, which can diminish the impact of NEPA’s procedures for considering environmental impacts.

The Council of Environmental Quality (CEQ), a small agency within the Executive Office of the President, issues implementing regulations for NEPA that outline how federal agencies must comply with NEPA. The CEQ NEPA implementing regulations outline a framework but are designed to provide flexibility to each agency. The CEQ regulations require every agency to adopt its own NEPA implementing procedures to supplement the CEQ regulations, which are reviewed by CEQ.

CEQ’s regulations have only been significantly revised once since their inception in 1978. However, under the Obama administration the CEQ issued new guidance on how agencies should consider greenhouse gas emissions and climate change in their NEPA reviews. The Trump administration has taken its first step to revising the CEQ regulations by releasing a set of twenty questions for public comment. The sweeping nature of the questions and topics covered indicate the administration may pursue dramatic revisions to the regulations environmental reviews. The questions focus on environmental review efficiency and ask for broad comments, even going so far as to consider changing the definitions of fundamental terms. The Trump administration also revoked guidance that assisted agencies with assessing the greenhouse gas footprint of major federal actions during the NEPA review process and has instructed agencies to review their internal NEPA procedures with a focus on streamlining the NEPA review process.


On February 18, 2010 the Council on Environmental Quality (CEQ) proposed guidance to agencies for considering greenhouse gas emissions and climate change in NEPA reviews.

In December, 2014 CEQ updated its proposal for climate change NEPA guidance.

On August 1, 2016 CEQ finalized Guidance on the Consideration of Greenhouse Gas Emissions and the Effects of Climate Change in NEPA Reviews.

Trump Era­ 

White House, CEQ, and Multi-Agency Actions 

On March 28, 2017 President Trump signed Executive Order 13783 on Promoting Energy Independence and Economic Growth which directed CEQ to rescind final guidance issued on August 1, 2016 on the Consideration of Greenhouse Gas Emissions and the Effects of Climate Change in NEPA Reviews.

On August 15, 2017, President Trump signed Executive Order 13807 that shortened the time for environmental reviews of large federally-funded infrastructure projects. This order also revoked President Obama’s Executive Order 13690, which had required federal agencies to consider sea level rise and flood projections when considering agency actions, including federal funding of infrastructure. This order established the “One Federal Decision” approach to NEPA reviews for major infrastructure projects, requiring each project to have a single lead agency for the environmental review process. The order instructed CEQ and OMB to develop a framework for this implementing the One Federal Decision and directed CEQ to develop an initial list of actions it plans to take to revise the environmental review process within 30 days. This order also kicked off actions within agencies to review and revise their NEPA process with regard to infrastructure projects.

On September 14, 2017, CEQ published its initial action list for revising the NEPA process as required by EO 13807.

On February 12, 2018, President Trump released the Legislative Outline for Rebuilding Infrastructure in America. The President’s plan calls on the White House Council on Environmental Quality to rewrite its NEPA regulations, which would have a significant impact on all agencies’ NEPA processes. President Trump’s plan proposes designating one lead agency for each NEPA review, rather than the current approach that requires independent review of the action from each relevant agency. This would mean that expert agencies, such as public health and environmental agencies, would not have meaningful input in the environmental review process. The proposal also limits the allowable time for environmental review and decreases the period of time in which a lawsuit may be filed challenging a NEPA review. Additionally, the proposal would limit the authority of the Environmental Protection Agency to oppose projects based on expected increases in air pollution.

On April 9, 2018, the MOU Implementing One Federal Decision Under Executive Order 13807 was signed by 12 federal agencies and councils.

On June 20, 2018, CEQ issued an Advanced Notice of Proposed Rulemaking to update its NEPA implementing regulations. CEQ solicits comments on 20 broad questions regarding the NEPA process and scope of NEPA review and asks for specific recommendations for changes to the regulations. The comment period closed July 20, 2018.

On July 11th, CEQ extended the comment period through August 20, 2018.

Click the links below for Agency-specific NEPA updates

Department of Interior

USDA – Forest Service

Department of Homeland Security

Federal Communications Commission

Federal Energy Regulatory Commission


Thank you to Harvard student Laura Bloomer, JD/MPP 2019 for her assistance with this rule.

HLS Student Orgs

Search Our Site

HLS Evironmental Law on Twitter