For decisions on the same proposal, existing SEPA documents can be revised and supplemented to provide new information. Instead of preparing a new environmental checklist or Environmental Impact Statement (EIS), agencies can adopt and use previous reviews that include a relevant analysis of all or part of a new proposal.
Revising SEPA documents for the same proposal
The lead agency is responsible for completing the environmental review process for all agencies with jurisdiction. This means other agencies with jurisdiction do not prepare separate SEPA documents or adopt the environmental documents issued by the lead agency for the same proposal.
However, SEPA documents do not have arbitrary expiration dates and can be modified — including revised Determinations of Nonsignificance (DNS), EIS Addendums, or Supplemental EIS — to better inform a pending agency decision. Modifying, revising, and supplementing exiting SEPA documents can be done for the same proposal.
If a DNS or mitigated determination of nonsignificance (MDNS) was previously issued and new information warrants additional analysis, the lead agency can withdraw or modify the DNS and issue a Revised DNS with additional supporting information such as a new staff report, or a new or revised checklist or addendum.
A draft EIS can be modified using an addendum or changes can be reflected in a revised draft EIS. A final EIS can be modified by issuing an addendum or supplemental EIS.
If a proposal is delayed so new permits must be applied for after SEPA review is done, then the additional review process could be limited to:
Any notice and comment provided for the underlying permit should still include previous SEPA documents to ensure the permitting agency considers any new or additional information.
- Verifying that there is no new environmental information.
- Determining regulatory changes or changes to the proposal require additional SEPA review.
Adopting previous SEPA reviews for new proposals
If the impacts associated with a new proposal have been adequately evaluated in a previously-issued SEPA or NEPA document, the document can be adopted to satisfy SEPA requirements. While a lead agency may adopt all or part of the information and environmental analysis in the adopted documents, they will need to make a new threshold determination.
Using existing documents is particularly important cities and counties planning development under the state Growth Management Act (GMA). Jurisdictions that have completed an environmental analysis for their comprehensive plans and development regulations can use the analysis as starting point for reviewing individual projects, allowing them to focus just on those aspects that have yet to be addressed. GMA cities and counties can also use the new Planned Action process in which formal SEPA review is done before proponents submit permit applications for projects.
Agencies can only use documents from a previous SEPA or NEPA review. This is why it is critical to provide a thorough description of the current proposal and clearly identify the SEPA documents being adopted.
In addition, agencies adopting existing environmental documents must independently determine if they meet environmental review standards and a proposal's needs. To be adopted, previous SEPA documents are not required to meet an agency's own preparation procedures. However, in all cases, agencies are required to issue new threshold determinations. They can use the following previous SEPA documents:
When adopting a document, a copy must be available for review — although the lead agency is not required to recirculate copies with the adoption notice, except to agencies with jurisdiction that have not already received them. Agencies are encouraged to distribute copies of adopted or incorporated SEPA documents to agencies with expertise or interest in the proposal, as well as affected tribal governments. Include the SEPA determination whenever possible since these documents assist in adequately evaluating a proposal.
- Adoption / determination of significance (DS) is issued when an existing EIS addresses all probable significant adverse environmental impacts and reasonable proposal alternatives. While a new comment period is not required, a agency must distribute the adoption notice. There is a 7-day waiting / reading period before an agency can take an action.
- Adoption / DS and addendum follows the same procedure as the adoption / DS, except an addendum adding minor new information is circulated with the adoption notice.
- Adoption / DS and Supplemental EIS is used when an existing EIS addresses some, but not all, of a new proposal's probable significant adverse environmental impacts. The EIS can be used as the basis for a new supplemental EIS and the adoption notice must be included in the draft and final supplemental EIS.
- Adoption / Determination of Nonsignificance is used for existing DNS and environmental checklist, NEPA environmental assessment, or documented categorical exclusion is adopted for a new proposal using the combined adoption / DNS template. The agency must follow DNS procedures including a comment period, distribution, and public notice.
Incorporation by reference
Incorporation by reference is similar to directly adopting a previous SEPA document. This is because all or part of the incorporated document becomes part of the agency environmental documentation for a proposal. Unlike the adoption process which is limited to environmental documents issued under either SEPA or NEPA, any information may be incorporated by reference such as studies or reports that provide information relevant to a proposal. To incorporate documents by reference, the agency must identify and describe the documents in the current environmental checklist, threshold determination, or EIS.