CTS Printex operated a printed circuit board manufacturing facility in Mountain View, California from 1966 to 1985. The facility discharged metals and volatile organic compounds (VOCs), including trichloroethene (TCE), into soils and groundwater. EPA added the site to the Superfund National Priorities List (NPL) in 1990. EPA has identified 27 contaminants of concern across groundwater, soil, and soil gas. These include chlorinated solvents such as TCE, tetrachloroethene, 1,1,1-trichloroethane, dichloroethane and dichloroethene compounds, as well as benzene, toluene, chloroform, and vinyl chloride.
Cleanup began in 1985 with soil removal and installation of a groundwater extraction system. From 1987 to 1996, that system pulled out roughly 100 pounds of TCE and more than 106 million gallons of contaminated groundwater. The system was shut down in 1996 when it became inefficient. In 2011, EPA issued a Record of Decision Amendment adding new remedies, including enhanced anaerobic bioremediation, which uses naturally occurring microorganisms to break down VOCs, along with monitored natural attenuation and institutional controls restricting groundwater use. Vapor intrusion mitigation measures were also implemented. Soil cleanup is now complete. Groundwater cleanup is ongoing.
A developer acquired the former CTS Printex property in 2006 and completed a residential townhome development by 2010. EPA worked with the developer to ensure the site could safely support residential use. Vapor intrusion controls were put in place, and institutional controls were established to evaluate risks during any future construction or renovation. Public drinking water in Mountain View is safe and meets all state and federal standards. Groundwater beneath the site is not used for drinking water, and institutional controls restrict access to contaminated areas. Human exposure is under control, and groundwater migration is stabilized.
EPA completed its sixth Five-Year Review on September 29, 2025. The review confirmed the remedy continues to protect human health and the environment. The next Five-Year Review is scheduled for completion by September 30, 2030. The site has not yet been deleted from the NPL.
Community members with questions can contact the EPA Remedial Project Manager. Site records are also available at the EPA Regional Records Center in San Francisco, located at 75 Hawthorne Street, Room 3110, and reachable at (415) 947-8717.
