Environmental Impact Assessment

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Editor: William A. Darity, Jr.
Date: 2008
Publisher: Gale
Document Type: Topic overview
Length: 1,358 words
Content Level: (Level 5)
Lexile Measure: 1360L

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Environmental Impact Assessment

An environmental impact assessment (EIA) is a planning tool that provides decision makers with an understanding of the potential effects that human actions, especially technological ones, may have on the environment. By understanding the potential environmental effects of an action, policymakers can choose which should proceed and which should not. Governments from around the world perform environmental impact assessments at the national, state or provincial, and local levels. The underlying assumption of all environmental impact assessments is Page 606  |  Top of Articlethat all human activity has the potential to affect the environment, and that knowledge concerning the environmental impact of a major decision will improve that decision. As part of an EIA, planners try to find the ways and the means to reduce the adverse impacts of the project and to shape projects to suit the local environment. EIAs can produce both environmental and economic benefits, such as reducing the costs and time needed for project implementation and design, avoiding treatment and clean-up costs, and alerting planners to any potential clashes with laws and regulations.

The original and probably best-known form of the EIA is the environmental impact statement (EIS) used by the U.S. government. The National Environmental Policy Act of 1969 (NEPA) mandates that an EIS must accompany every major federal action or nonfederal action with significant federal involvement within the United States. The precise definition of “major” and “significant” has been very contentious and has resulted in considerable litigation. The NEPA ensures that U.S. agencies give environmental factors the same consideration as any other factors in decision making.

Since 1970 dozens of other nations have established their own versions of an EIA, partly on their own and partly in response to the call of a number of international meetings. In particular, the seventeenth principle of the Rio Declaration on Environment and Development (1992) is devoted to the creation of processes for environmental impact assessments by governments around the world.


Most environmental impact assessments follow a process similar to the one mandated for the EIS, in which a lead agency collects and assimilates all the environmental information required for the EIS (Sullivan 2003). The first step in the process is to determine whether a complete EIS is required. When there is likely to be little impact, the lead agency can write an environmental assessment (EA), which is much simpler. In the late 1980s agencies annually prepared only 450 complete environmental impact statements, compared to an average of 15,000 environmental assessments (Gilpin 1995).

The first element of the actual EIS is scoping, where the lead agency identifies key issues and concerns of interested parties. A notice of the intent to conduct an EIS is published in the Federal Register and is sent to all potentially interested parties. Usually, the agency releases a draft environmental impact statement (DEIS) for comment. After interested parties and the general public have had the opportunity to comment on the draft, the agency releases the final environmental impact statement (FEIS).

In some instances, usually as the result of litigation or the availability of new information, the agency later releases a supplemental environmental impact statement (SEIS). Once all the protests are resolved the agency issues a record of decision, which is its final action prior to implementation.

The Council on Environmental Quality (CEQ), also mandated by the NEPA, sets the regulations that outline the format for the actual EIS. They mandate that an EIS should contain the impact of the proposed action, any adverse environmental effects that cannot be avoided, any possible alternatives to the proposed action, and any irreversible commitments of resources that the action would require if it were implemented. All mitigation measures to address identified harms must also be included in the EIS. Throughout the EIS process, the public must have opportunities for participation (Sullivan 2003). In 1994 President Bill Clinton issued an executive order adding environmental justice issues to the EIS process.


One of the problems with environmental impact assessments is that in many cases, after the factors have been analyzed, there is little to force the actors to change their decisions. Once the EIA is complete, the action can go forward regardless of any negative environmental consequences. In the case of the EIS, the NEPA provides no enforcement provisions, though various court decisions have held that an EIS must be done and that it should be used to inform decision makers of potential environmental problems. However, at present nothing requires planners to change their decisions based on an EIS’s findings, nor is there any penalty for ignoring an EIS. In the early 1970s groups trying to stop an action used EISes to initiate numerous lawsuits. At the end of the 1970s the U.S. Supreme Court in Vermont Yankee v. NRDC (1978) reversed two district court decisions remanding the NRC for not addressing environmental issues adequately in their EIS. This decision limited the ability of district courts to reverse agency decisions (Vig and Kraft 2000). By the end of the 1980s the federal courts consistently declined to hear lawsuits on environmental issues if the EISes were properly done. According to the courts, planners may elect to include or exclude EIS findings from their projects, and if they choose to ignore it, others have a right to bring pressure on them. The CEQ cannot stop an action, but it can delay it by requesting further reassessment.

Another problem with the creation of EIAs springs from the uncertainty surrounding some situations. Uncertainty may come from a lack of scientific understanding Page 607  |  Top of Articleof an issue or from the nature of the information required. The issues may be extremely complex, or may deal with timescales that create potential problems for understanding the issue. For example, the proposed nuclear waste facility at Yucca Mountain, Nevada requires the consideration of environmental changes at the site over a 10,000-year period. The Yucca Mountain case also provides an example of another problem—the quality of the information used in creating an EIS. It was discovered that the researchers doing the assessment at Yucca Mountain manufactured some of the information they used for the EIS; a subsequent government study ruled that even though the data was suspect, the overall decision based on it was sound (Department of Energy 2006). For some governments around the world, the lack of resources and skilled personnel create problems for producing a quality EIA.

This is not to say that identifying environmental issues has no effect on the decision-making process. A number of studies have shown that EISes force greater environmental awareness and more careful planning by federal agencies (Vig and Kraft 2000). The very fact that the information exists means it plays a role. The EIS is circulated among state, local, and federal agencies and the public. Because of this circulation, the EIS can become an early warning system for environmental groups, alerting them of potential issues for their consideration (Rosenbaum 2005). The identification of potential problems has motivated public support against actions and led to rethinking of initial plans. Having the information is better than not having information, even though it may not be used.


Department of Energy. 2006. Evaluation of Technical Impact on the Yucca Mountain Project Technical Basis Resulting from Issues Raised by Emails of Former Project Participants. DOE/RW-0583 QA:N/A, April.

Gilpin, Alan. 1995. Environmental Impact Assessment (EIA): Cutting Edge for the Twenty-First Century. Cambridge, U.K.: Cambridge University Press.

Rosenbaum, Walter A. 2005. Environmental Politics and Policy. 6th ed. Washington, DC: CQ Press.

Sullivan, Thomas F. P. 2003. Environmental Law Handbook. 17th ed. Rockville, MD: ABS Consulting Government Institutes.

Vig, Norman J., and Michael E. Kraft. 2000. Environmental Policy. 4th ed. Washington, DC: CQ Press.

Franz Foltz

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Gale Document Number: GALE|CX3045300724