Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to page options Skip directly to site content

NEPA Frequently Asked Questions

This website is archived for historical purposes and is no longer being maintained or updated.

The Healthy Community Design Initiative, also known as the Built Environment and Health Initiative, is no longer a funded program and the information on this website is not being reviewed and updated on a regular basis.


What is NEPA?

The 1971 National Environmental Policy Act (NEPA) requires federal agencies to consider environmental impact while planning and deciding on new projects and policies. NEPA’s purpose is to ensure that before significant federal actions occur, environmental impact information is available to both public officials and citizens. To achieve this, NEPA requires that each federal agency take into consideration the environmental consequences of its proposed actions. At the initial review stage, the project might not meet the criteria for impact review; it would then be excluded from further environmental consideration. If, however, the project might have environmental consequences, the agency proceeds to the next step, which could be preparation of an Environmental Assessment (EA). If the environmental consequences appear significant, the agency prepares an Environmental Impact Statement (EIS)—a more detailed environmental analysis. Thus the entire environmental impact assessment process could lead to

  • A finding that the project or plan is categorically excluded from NEPA consideration,
  • An Environmental Assessment resulting in a Finding of No Significant Impact (FONSI) or in a finding of significant environmental impact necessitating an Environmental Impact Statement (EIS), or
  • An initial finding that the project might indeed have significant environmental consequences, thus necessitating an Environmental Impact Statement (EIS).

A broad range of actions can trigger NEPA. They include issuing regulations, making policy, providing permits for private actions, funding private actions, making federal land management decisions, and constructing publicly owned facilities.

Source: National Environmental Policy Act (NEPA) Basic Information. US Environmental Protection Agency. 2012. [cited 2012 Aug 22]. Available from URL:

 Top of Page

Why does a public health agency have a role in environmental policy?

The interaction between people and their environments, natural as well as human-made, continues as a major public health issue. Decisions that affect the natural environment’s air, water, or undeveloped lands, as well as decisions that affect the built environment’s communities and transportation systems, almost inevitably affect the health and well-being of all species—humans and nonhumans alike—that depend on them.

The purpose of NEPA is to

. . . promote efforts which will prevent or eliminate damage to the environment and biosphere and stimulate the health and welfare of man. NEPA § 102 [42 USC §4321]

As well as to

. . . assure for all Americans safe, healthful, productive, and aesthetically and culturally pleasing surroundings. [42 USC §4331]

And to

. . . attain the widest range of beneficial uses of the environment without degradation, risk to health or safety, or other undesirable and unintended consequences. [42 USC §4331]

As much as NEPA focuses on environmental protection, its purpose to protect and promote health is also clear. The above language gives local, state, tribal, and federal public health agencies the opportunity to engage with other agencies in an environmental impact assessment process that will adequately protect and promote public health.

 Top of Page

How is an Environmental Assessment (EA) or an Environmental Impact Statement (EIS) related to a Health Impact Assessment (HIA)?

EA/EIS and HIA all are tools that inform decision makers, before construction or implementation, about the potential environmental and health impacts of proposed projects, programs, or policies. While EA/EIS generally assess a broad range of environmental issues, such as air and water quality and effects on wildlife, HIA evaluates how proposed actions will affect human health through, for example, physical activity levels, respiratory health, injury, or nutrition.

Unlike EA/EIS, HIA is not a required review process. NEPA mandates EA/EIS when appropriate, while federal agencies, local or regional governments, the community, or others voluntarily initiate HIA. Nevertheless, NEPA requires incorporation of impacts on the human health environment into its comprehensive impact analysis. When federal actions have significant potential health impacts, HIA can be adapted to meet NEPA’s legal standards and administrative processes and CEQ regulations (see Table 1). A number of federal agencies have recently begun voluntarily to use HIA to comply with NEPA’s health mandate. Thus HIA can be used both inside and outside the NEPA process.

Table 1: Phases of HIA compared with Integrated HIA-environmental impact assessment (EIA) in NEPA

HIA Phase Integrated HIA/EIA

Determine whether an HIA is:
Likely to be beneficial

(1) Screening:

Under NEPA, federal agencies determine the need for an Environmental Impact Statement (EIS) by determining whether the action being evaluated is a “major federal action significantly affecting the quality of the human environment” (NEPA Sec. 102 [42 USC § 4332]). One of the considerations in determining “significance” is “the degree to which the proposed action affects public health or safety” (40 CFR 1508.27). Hence, NEPA essentially builds in screening for a possible HIA .


Population impacted
Geographic limits
Scope of health concerns to be addressed
HIA team
Data sources

(2) Scoping:

For an integrated HIA-EIA, the scope of health analysis is determined through the same process as other resource areas typically considered in an EA/EIS, that is, public health experts use public testimony, initial literature review, and evaluation to determine the appropriate scope of the analysis. A health scoping summary is submitted to the lead agency.

Assessment, or Appraisal:

Baseline: describe the baseline health status and determinants of health in the affected population

Assessment of impacts: uses qualitative or quantitative methods, literature review, expert analysis to project potential public health effects

(3) Assessment involves three steps:

a. Description of the Affected Environment: relies on the economic, sociocultural, employment, and demographic discussions in the EA/EIS, in addition to multiple public health data sources, including published studies, “grey literature,” vital statistics, health registries, and public testimony. Data gaps may result in the need for baseline data collection.

b. Environmental Consequences of the Alternatives (equivalent to Assessment of impacts in HIA): We identify evidence-based causal pathways between impacts described in other portions of the EA/EIS document (environmental, sociocultural, and economic), and health outcomes. The methodology is often descriptive, because the impacts on which health depends are often discussed qualitatively in the EA/EIS document. Quantitative modeling is rare.

c. Recommendations: in an integrated HIA-EIA, measures to protect health are developed and analyzed together with the impact analysis, and proposed either as mitigation measures or as alternative modifications.


Recommendations are made for measures that could be taken to protect and promote health.


The results are reported to the public and decision makers.

(4) Reporting: The Public Health information is reported in subsections in the Draft EIS (DEIS); the DEIS is reassessed based on public comments, and a Final EIS (FEIS) issued.

The HIA results are evaluated, and monitoring of expected outcomes may be instituted

(5) Decision-making: Using the information in the FEIS, agency management renders a final decision approving, modifying, or rejecting the proposed action. This is called the “Record of Decision.”

(adapted) Table courtesy of Aaron Wernham, MD, MPH, unpublished.


 Top of Page

As a community member who wants to ensure human health impacts are assessed in an EIS in my area, how can I help make this happen?

The environmental review process under NEPA provides an opportunity for community involvement in the federal decision-making process. Active involvement in the NEPA process requires a commitment of time and a willingness to share information with the decision-making agency and other citizens. Several opportunities are available for involvement in the NEPA process:

  • During the mandated public comment period when the agency prepares its NEPA report.
  • Before and during preparation of a NEPA analysis.
  • When a NEPA document is published for public review and comment.
  • Through monitoring implementation of the proposed action and the effectiveness of any associated mitigation.

If you are a citizen interested in actions taking place in a particular area, community, or ecosystem, let the appropriate agency know that you would like to be notified of any EAs, or, especially, EISs in that area. Another way to participate is to ask local experts such as public health or environmental health officers to assist with your review of NEPA analyses and documents for public health impact. Many communities form interest groups and action teams to collaborate on activities such as HIA in NEPA.

A helpful resource is the CEQ booklet, A Citizen’s Guide to the NEPA: Having your Voice Heard.

 Top of Page

As a federal agency representative leading a NEPA project, how can I make sure health impact is adequately addressed?

One of your agency’s NEPA responsibilities is to ensure an adequate assessment of impacts to the human environment is carried out, including health impacts. To do this, the Lead Agency might partner with local, state, tribal, or federal public health agencies through cooperating agency status, interagency agreements or in other, less formal ways. An HIA might be conducted through such partnerships or by collaborating with appropriate community-based organizations, HIA consultants, or using in-house expertise. Many resources are available for ensuring that health is adequately considered in your NEPA project. See CDC’s Resources section below, or contact CDC at with “NEPA-Federal Agency Inquiry” in the subject line.

To find out more about Cooperating Agency status in NEPA, go to

Go to CDC’s NEPA homepage

 Top of Page