Navy conducts a Five-Year Review at Former NAS Moffett Field for environmental safety.

Public Notice Discretionary Five-Year Review Installation Restoration Site 28 Former Naval Air Station Moffett Field Moffett Field, California May 2026 The United States Department of the Navy (Navy) is currently conducting a Discretionary Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Five-Year Review at Site 28 of the Former Naval Air Station (NAS) Moffett Field, California. Former NAS Moffett Field is located 35 miles south of San Francisco and 10 miles north of San Jose. The Navy is conducting the Discretionary Five-Year Review in accordance with the requirements of CERCLA Section 121(c). The purpose of the Discretionary Five-Year Review is to satisfy a requirement in an agreement between the Navy and the National Aeronautics and Space Administration (NASA) related to the transfer of environmental liability. Within this Discretionary Five-Year Review, the Navy will reconfirm the vapor intrusion (VI) remedies selected for implementation in the Middlefield-Ellis-Whisman (MEW) Study Area Record of Decision (ROD) Amendment [EPA, 2010] for Installation Restoration (IR) Site 28 are and remain protective of human health and the environment. IR Site 28 Background: IR Site 28 is underlain by chlorinated VOC groundwater plumes attributable to Navy sources west of the Moffett Field runways. The Navy release is comingled with other regional plumes that are being addressed as the Middlefield-Ellis-Whisman (MEW) Study Area. The remedy for groundwater at IR Site 28 is extraction and ex situ treatment to restore groundwater to the cleanup standards specified in the MEW Study Area ROD (EPA, 1989). In August 2010, EPA amended the MEW Study Area ROD to select remedies for the VI pathway to mitigate volatile contaminants in groundwater from migrating into buildings (MEW Study Area ROD Amendment [EPA, 2010]). The Navy's Final Fifth Five-Year Review Report dated February 2025 (2025 Five-Year Review Report), determined that the groundwater and VI remedies at IR Site 28 are currently protective of human health and the environment. Following finalization of the 2025 Five-Year Review Report, the Navy transferred long-term management responsibility of the groundwater remedy at Site 28 to NASA, the property recipient and owner of the former NAS Moffett Field. Upon completion of this Discretionary Five-Year Review Report, with regulatory agency concurrence of remedy in place (RIP) for the VI systems at Site 28, NASA will assume long-term management for the VI remedy and emerging requirements at the site. The Navy will issue another Public Notice announcing the completion of this Discretionary Five-Year Review, which is anticipated to occur in December 2026. Questions or comments on the preparation of this Discretionary Five-Year Review or other Navy environmental activities at the Former NAS Moffett Field may be directed to: Dave Darrow Naval Facilities Engineering Systems Command (NAVFAC) Base Realignment and Closure Environmental Coordinator 33000 Nixie Way, Building 50, Suite 207 San Diego, CA 92147 (619) 524-4603 david.c.darrow.civ@us.navy.mil FOR MORE INFORMATION Additional information and key documents for sites at the Former NAS Moffett Field are available at www.bracpmo.navy.mil and at the locations listed below. Information Repository Administrative Record Mountain View Public Library Contact: Ms. Diane Silva NAVFAC Southwest 585 Franklin Street, 1220 Pacific Highway, Code EV33 Mountain View, CA 94041 Naval Base San Diego, Building 3519 (650) 903-6887 San Diego, CA 92132 619 -556-1280 SJMN 6966223 May 6, 2026