Welcome to the Department of the Air Force’s (DAF) Supplemental Environmental Impact Statement (SEIS) for the evaluation of potential environmental effects associated with changes to the Proposed Action for deployment of the Sentinel intercontinental ballistic missile system. The SEIS addresses design refinements and facility siting updates that have occurred since completion of the March 2023 EIS for Sentinel (GBSD) Program Deployment and Minuteman III Decommissioning and Disposal and the May 2023 Record of Decision (ROD). The “Sentinel Weapon System Program” (“Sentinel Program” from this point forward) addressed in the 2023 EIS and the ROD was formerly known as the “Ground Based Strategic Deterrent (GBSD).” This website will be updated periodically as the SEIS is developed.

The Bureau of Land Management, Bureau of Reclamation, and U.S. Army Corps of Engineers will continue in their roles as Cooperating Agencies from the 2023 EIS. The Bureau of Indian Affairs, U.S. Fish and Wildlife Service, U.S. Forest Service, and U.S. Department of Agriculture Farm Service Agency are invited to participate as Cooperating Agencies. The DAF will consult with, and obtain the comments of, federally recognized Native American Tribes and federal agencies that have jurisdiction by law or special expertise related to the environmental analysis. 

Information about the proposed changes to the Sentinel Program, the National Environmental Policy Act process, and Section 106 of the National Historic Preservation Act is available in the “Project Information” drop-down menu at the top of this page. 

A public scoping period of 30 days will take place starting from the date of publication of the Notice of Intent (NOI) in the Federal Register. The content of the NOI is also available at the top of this page. The DAF requests comments on alternatives, impacts, relevant information, studies, or analyses with respect to the Proposed Action. Scoping comments may be submitted using the “Provide Comments” tab at the top of this page, by email to SentinelSEIS@tetratech.com with “Sentinel SEIS” in the subject line, or by U.S. mail to Sentinel SEIS, c/o Tetra Tech, 711 Navarro Street, Suite 560, San Antonio, TX 78215. The Draft SEIS is anticipated to be available for public comment in fall 2027. The Final SEIS is anticipated for publication in spring 2028. 

SEIS inquiries and requests for digital or print copies of the information provided on this website are available upon request at the email or mailing address provided.