National Environmental Policy Act: Frequently Asked Questions

When does NEPA apply?

NEPA applies whenever a proposed activity or action:

  • is proposed on federal lands;
  • requires passage across federal lands;
  • is to be funded – either entirely or in part – by the federal government; or
  • affects the air or water quality that is regulated by federal law.

When any one of these four conditions are present, the federal agency with the greatest expertise, regulatory authority, and capacity to manage the NEPA process for the proposed project becomes the lead agency for that project.

Back to top

What is the purpose of an Environmental Assessment/Environmental Impact Statement?

An Environmental Assessment (EA) is prepared to determine if a federal action will have significant impacts and to address unresolved environmental issues. The EA may provide the rationale for a decision on a proposed action. Any action that is not categorically excluded and does not require an Environmental Impact Statement (EIS), has impacts that are uncertain, or has unresolved environmental issues, requires preparation of an EA. In addition, an EA may be prepared to assist planning or decision-making, simplify permit approval or help obtain other necessary legal clearances.

An EIS is used by federal agencies, in conjunction with other relevant information, to plan actions and make decisions. The primary purpose of an EIS is to ensure that a full and fair discussion of all significant environmental impacts occurs and to inform decision-makers and the public of reasonable alternatives that would avoid or minimize adverse impacts or enhance the quality of the human environment.

Back to top

What is a categorical exclusion?

Categorical exclusions are classes of actions that do not individually or cumulatively have a significant effect on the human environment. Actions that are categorically excluded do not require the preparation of an EA or EIS. An EA or EIS must be prepared if an action would normally be categorically excluded but may result in significant impacts on the human environment, or if the action is covered by extraordinary circumstances. If it is determined that a proposed action is a categorical exclusion and the extraordinary circumstances do not apply, the action can be implemented immediately.

Back to top

What is the Service's role in the NEPA process?

The Service's Ecological Services Program is responsible for coordinating Service responsibilities for proposed actions, including planning activities, subject to NEPA. The program prepares NEPA policies, directives, guidance and training materials for Service personnel related to environmental review and other related matters. Mitigating for impacts to sensitive habitats is part of the planning process. The Service's Mitigation Policy guides Service biologists in the development of appropriate mitigation measures designed to nullify the impacts of planned activities. The Mitigation Policy directs biologists to the most current methods for identifying mitigation areas across the landscape to accomplish the most effective and efficient conservation.

Service actions that may require NEPA documentation include issuance of permits or licenses, land acquisition, establishment of national wildlife refuges and national fish hatcheries, operation and management of lands and waters administered under the NWR and NFH systems, issuance of regulations, policies, procedures, and guidance, and issuance of financial assistance, including grants, cooperative agreements and private land restorations. The Service is involved in the preparation of about 65 environmental impact statements and 1,000 environmental assessments annually. In addition, the Service reviews more than 2,000 environmental documents annually from other federal agencies, providing comments from Service field, regional, and other offices and facilities.

Back to top

How does the public play a role in the NEPA process?

Public participation is an integral part of NEPA's procedural requirements. Public participation is accomplished through the scoping process, an important step in the early planning stage of an environmental document. The objective of scoping is to identify significant issues and initiate community-based planning and collaboration to determine the action, why it is being considered and to outline what is needed to conduct the action. Scoping is also used to identify potential impacts associated with project alternatives, which need to be addressed in the EA and EIS. Scoping reduces paperwork, delays and costs, and improves the effectiveness of the NEPA process. Public participation in scoping is initiated through notices in local newspapers, direct mailings, Federal Register notices and other public documents. The Service makes every effort to understand public concerns, accurately record public comments and allow adequate time for involvement by the affected public.

Back to top


A rocky shoreline of a river. The water is calm. Mist and green branches line the river.
The Ecological Services Program works to restore and protect healthy populations of fish, wildlife, and plants and the environments upon which they depend. Using the best available science, we work with federal, state, Tribal, local, and non-profit stakeholders, as well as private land owners, to...