Welcome to the U.S. Navy's website for the Northwest Training and Testing Supplemental Environmental Impact Statement/Overseas Environmental Impact Statement (EIS/OEIS).

On Sept. 23, 2021, the Navy released its Record of Decision to continue training and testing activities at sea and in associated airspace within the Northwest Training and Testing (NWTT) Study Area, referred to as the "Study Area," as described in the NWTT Final Supplemental Environmental Impact Statement/Overseas Environmental Impact Statement (EIS/OEIS). The Navy selected Alternative 1, its Preferred Alternative, after considering its operational needs; potential environmental impacts; and comments from elected officials, government agencies, tribes, nongovernmental organizations, and the public.

The Navy prepared the supplement to the 2015 NWTT Final EIS/OEIS to assess the potential environmental impacts associated with proposed ongoing and future activities conducted at sea and in associated airspace within the Study Area beyond 2021. Proposed activities are similar to those that have occurred in the Study Area for decades and that were previously analyzed in the 2015 document.

The Final Supplemental EIS/OEIS supports the issuance of federal regulatory permits and authorizations under the Marine Mammal Protection Act and the Endangered Species Act. The Final Supplemental EIS/OEIS includes an analysis of training and testing activities using new, relevant information available after the release of the 2015 NWTT Final EIS/OEIS. New information includes more recent marine mammal density data and new scientific information.

Watch an informational video about the importance of Navy training and testing in the Study Area.