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Environmental impact statement process

We provide information and guidance about the Environmental Impact Statement process under SEPA.

An Environmental Impact Statement (EIS) is prepared when the lead SEPA agency determines a proposal is likely to have significant adverse environmental impacts. The EIS process is a tool for identifying and analyzing:

  • Probable adverse environmental impacts
  • Reasonable alternatives
  • Possible mitigation

The EIS process:

  • Provides opportunities for the public, local, state and federal agencies, and tribal governments to participate in developing and analyzing information. This input helps identify a proposal's significant adverse environmental impacts, reasonable alternatives, possible mitigation measures, and methods for analyzing the EIS. Public participation during all process phases increases understanding of the proposal and garners trust.
  • Improves proposals from an environmental perspective. Proposals are improved by identifying adverse environmental impacts, reasonable alternatives and potential mitigation measures that meet the objectives of a proposal. Changes can made voluntarily by the proponent, or mitigated through SEPA substantive authority or other regulatory authority. The EIS process helps identify areas of controversy and other significant issues early when opportunities to consider a broad range of solutions are greatest.
  • Provides decision-makers with environmental information. An EIS provides decision-makers and the public with a complete and impartial discussion of the proposed project as well as existing site conditions, probable significant adverse environmental impacts, and reasonable alternatives and mitigation measures to avoid, minimize, or counter adverse impacts.
  • Provides necessary information for conditioning or denying a proposal. Based on information in the EIS and an agency’s adopted SEPA policies, SEPA substantive authority allows an agency to: Deny a proposal when impacts cannot be reasonable mitigated; place conditions on the project to protect the environment; or approve the proposal without further mitigation.

EIS process steps

The EIS process includes:

  • Conducting “scoping,” which initiates participation by the public, tribal governments, and other local, state and federal agencies to comment on a proposal’s alternatives, impacts, and potential mitigation measures to be analyzed in the EIS.
  • Preparing the draft EIS, which analyzes the probable impacts of a proposal and reasonable alternatives, and may include studies, modeling, and other information.
  • Issuing the draft EIS for review and comment by the public, tribal governments, and other local, state, and federal agencies.
  • Preparing the final EIS, which includes analyzing and responding to all comments received on the draft EIS, and may include additional studies and modeling to evaluate probable impacts.
  • Issuing the final EIS and using the information in decision-making.

There are two types of environmental impact statements:

  • A project EIS for proposals generally involving physical changes to one or more elements of the environment. Projects can include new construction; facility operation changes; environmental cleanup projects; demolitions; and purchases, sales, leases, transfers, or exchanges of natural resources.
  • A nonproject EIS prepared for planning decisions that provide the basis for later project review. Nonproject actions include the adoption of plans, policies, programs, or regulations that contain standards controlling the use of the environment or that will regulate a series of connected actions. Examples include comprehensive plans, watershed management plans, shoreline master programs, and development regulations.

Public participation

SEPA requires agencies to involve the public during:

  • The “scoping” period, where the public, tribal governments, and local, state, and federal agencies are invited to comment on the range of alternatives, areas of impact, and possible mitigation measures the EIS should evaluate. Public scoping meetings may be held.
  • The draft EIS review period, where comments are requested regarding the merits of alternatives and the adequacy of the environmental analysis. Public hearings are often held on a draft EIS.

Additional resources

  • For more detailed information about preparing an Environmental Impact Statements, see our SEPA Handbook, Chapter 3
  • For further information about the procedures for preparing an EIS, see state SEPA rules, Part 4 (Chapter 197-11 WAC, Sections 400 to 460).