There are three types of environmental reviews an agency can require for a proposed major federal action: an environmental assessment, an environmental impact statement, or a categorical exclusion. 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.
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 (FONSI) and does not need to prepare an environmental impact statement.
Agencies can also adopt categorical exclusions (CEs), which are classes of actions that the agency determines do not generally have a significant effect on the human environment, and therefore do not require an EA or an EIS. 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. Congress amended NEPA in 2023 to also allow an agency to adopt another agency’s CE. See 42 U.S.C. § 4336c.
CEQ’s Regulations Implementing NEPA
The Council of Environmental Quality (CEQ), a small agency within the Executive Office of the President, historically issued implementing regulations for NEPA that outlined how federal agencies should comply with the statute. CEQ’s NEPA implementing regulations created a single framework for environmental reviews, but were designed to provide flexibility to each agency consistent with its mandate and activities.
In February 2025, the District Court for the District of North Dakota vacated CEQ’s 2024 NEPA regulations (the Phase II rule), holding that CEQ lacked the authority to issue binding NEPA regulations. Shortly after, CEQ revoked all its NEPA rules and issued guidance requiring each federal agency to revise its NEPA regulations consistent with the 2023 amendments, using CEQ’s 2020 rule as a model and incorporating specific policy priorities.
Other Federal Agencies’ Rules Implementing NEPA
Federal agencies continue to be bound by their own NEPA implementing regulations. Most agencies’ rules, except the Department of Energy, are decades-old and inconsistent with NEPA as amended. According to CEQ’s Feb. 19, 2025 guidance, federal agencies will continue with pending and ongoing NEPA analyses while they revise their rules. Where agency rules are inconsistent with NEPA, CEQ’s guidance urged agencies to make “any adjustments needed” though the guidance does not state whether those adjustments will be subject to public notice and comment.
Current Status:
- Environmental Protection Agency (EPA) last updated its NEPA implementing regulations in 2007, with minor revisions in 2009.
- Department of Energy (DOE) finalized new NEPA implementing regulations on April 30, 2024 establishing new categorical exclusions for energy storage systems and incorporating the FRA amendments.
- Department of the Interior (DOI) last updated its NEPA implementing regulations in 2008.
- Department of Homeland Security (DHS) does not have NEPA implementing regulations. The agency last updated its NEPA guidance in 2015, with minor edits in 2017.
- Federal Communications Commission (FCC) last updated its NEPA implementing regulations in 1986.
- U.S. Department of Agriculture (USDA) last updated its NEPA implementing regulations in 1983, though many of the agency’s components have newer regulations:
- U.S. Forest Service (USFS) last updated its NEPA implementing regulations in 2008.
- Farm Service Agency (FSA) last updated its NEPA implementing regulations in 2016.
