Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
Westinghouse Electric Corp. (sunnyvale Plant)
EPA #: CAD001864081
County: Santa Clara
Congressional District: 14
On this page
Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 10/15/84
Final Date: 06/10/86
The 75-acre Westinghouse Electric Corporation (Sunnyvale Plant) site was formerly used to manufacture electrical transformers. It is currently used to manufacture steam generators, marine propulsion systems, and missile launching systems for the Department of Defense. Groundwater contamination is believed to have resulted from a leaking polychlorinated biphenyls (PCBs) storage tank and from localized spills. Most of the contaminated areas on site have been removed and/or have been paved over. Access to the site is restricted. Approximately 710,000 people live within three miles of the site. The nearest residence is located adjacent to the site. Approximately 300,000 people depend on groundwater within three miles of the site for their drinking water supply. There are no private wells within the vicinity of the site; however, area municipal wells are located within 1/4 mile of the site.
Contaminants and Risks
- Soil and Sludges
Groundwater and soil are contaminated with PCBs, fuels, and volatile organic compounds (VOCs). Potential health threats to area residents include accidentally ingesting or coming into direct contact with site contaminants in soil or groundwater.
Who is Involved
This site is being addressed through Federal and potentially responsible parties' actions.
Investigation and Cleanup Activities
This site is being addressed in two stages: immediate actions and a long-term remedial phase focusing on cleanup of the entire site.
Immediate Actions: Westinghouse removed contaminated soils in 1984 and 1985, and a gasoline tank in 1986.
Westinghouse completed an investigation into the nature and extent of contamination at the site in 1991. The EPA selected the following remedies to address groundwater and soil contamination: extracting and treating groundwater, conducting off-site incineration of soil contaminants, and implementing land-use restrictions at the site. The company, under the EPA's supervision, completed detailed specifications for the groundwater and soil cleanup plans in the summer of 1994. Construction of the remedies began in late 1994. Soils in the main plant areas and the underground storage tank area were removed in late 1994. Full-scale treatment of the contaminated groundwater began in early 1995 and will continue until established cleanup goals are met.
EPA completed a Five Year Review for the Westinghouse Site in September 2006. An evaluation of the site status and cleanup progress showed the site is protective of human health and the environment, and that the groundwater extraction and treatment system is functioning properly. The groundwater plume is contained within a portion of the site and does not extend to off-site monitoring wells. In order to ensure the site remains protective over the long term, deed restrictions need to be placed on the site to limit the use of the land to industrial or commercial uses. EPA issued an Explanation of Significant Differences (ESD) in 2008 to define the deed restrictions.
In 1984 and 1985, the State issued Waste Discharge Requirements to Westinghouse, requiring the company to conduct interim cleanup measures and to investigate the nature and extent of contamination at the site. In 1988, Westinghouse entered into an agreement to investigate the contamination problems at the site and to evaluate potential cleanup options. In 1992, Westinghouse entered into an agreement with the EPA to develop a detailed design of the cleanup activities. The EPA approved the final detailed design on June 28, 1994. Construction of the full-scale groundwater system was completed during May 1995.
Cleanup Results to Date
The removal of contaminated soil and a gasoline tank, and the operation of the groundwater treatment system has reduced the potential for exposure to contaminated materials at the Westinghouse Electric Corporation (Sunnyvale Plant) site. Cleanup activities will continue until established standards are met.
The most recent Five-Year Review of the remedy at the Westinghouse Electric Corp. site was completed in September 2011. The Five-Year Review identified follow-up items that will need to be addressed in order to ensure the protectiveness of the remedy. The review noted that shallow surface soil contamination above the cleanup level remains in place at some areas on site. This will be addressed by removing or capping within the next two years. The review also identified that institutional controls have not yet been placed on the site to prevent access to contaminated soils or groundwater. U.S. EPA, Northrop Grumman and the State of California will work together to place institutional controls on the site within the next year. Additionally, the review identified potential problems with the performance of the remedy. Progress towards achieving long-term groundwater restoration goals using extraction and treatment is limited. In the next year, Northrop Grumman will evaluate and characterize potential unaddressed source areas that may be contributing to upgradient groundwater contamination. They will also evaluate strategies, including active treatment technologies, to optimize the remedy and achieve long-term cleanup goals. Finally, the Five-Year Review identified a potential vapor intrusion pathway on site to an employee-occupied building. Northrop Grumman will conduct a screening to determine whether vapor intrusion is present at the Site. Due to the potential presence of vapor intrusion at the Westinghouse Site, a determination could not be made as to whether the site is currently protective of human health and the environment. A determination will be made when further information is obtained about the potential presence of a vapor intrusion pathway at the Site. The next review for the site will be completed in September 2016.
Potentially Responsible Parties
Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.
Online information about the PRPs for the site is not yet available.
Documents and Reports
Public Information Repositories
The public information repositories for the site are at the following locations:
Sunnyvale Public Library,
665 West Olive Avenue,
Sunnyvale, CA 94088
EPA Site Manager
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
700 Heinz Avenue,
Berkeley, CA 94710-2721
After Hours (Emergency Response)