![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
NPL Site Narrative for TRW Microwave, Inc (Building 825)
TRW MICROWAVE, INC. (BUILDING 825)
Sunnyvale, California
Federal Register Notice: February 21, 1990Conditions at proposal (June 24, 1988): The TRW Microwave, Inc. (Building 825) Site is located at 825 Stewart Drive, Sunnyvale, Santa Clara County, California. Three other sites are nearby: Advanced Micro Devices, Inc., placed on the NPL in June 1986; Signetics, Inc., proposed in October 1984 (and later dropped); and Advanced Micro Devices, Inc. (Building 915), also being proposed at this time. The sites are owned and operated by semiconductor/microprocessor manufacturers and have contributed to a commingled plume of ground water contaminated with organic solvents that has migrated off the sites to the north.
Contamination at Building 825 was first identified in April 1983 when a TRW contractor found up to 41,000 parts per billion (ppb) of trichloroethylene (TCE) in on-site wells. In May 1983, the California Regional Water Quality Control Board (CRWQCB) found that ground water beneath the building was contaminated with dichlorobenzene, tetrachloroethylene, TCE, acetone, N-butyl acetate, and xylene. Upgradient wells on the south side of the property showed only low levels of contamination, indicating that TRW is a point source of contamination.
In September 1983, TRW excavated soil at the site, removed an underground tank, and transported the materials to a hazardous waste facility regulated under Subtitle C of the Resource Conservation and Recovery Act. However, CRWQCB found that these measures did not correct the ground water contamination problem.
Contaminants from a leaking 750-gallon solvent storage tank at Building 825 have the potential to migrate to deeper drinking water aquifers. Municipal wells for Santa Clara and Mountain View tap a deep aquifer between 250 and 750 feet and serve an estimated 300,000 people. Imported surface drinking water is not considered an available alternative due to the size of the potentially affected population.
On June 21, 1984, CRWQCB issued a Cleanup and Abatement Order under the California Water Code requiring TRW Microwave, Advanced Micro, and Signetics to develop a joint plan to prevent further migration of contaminants.
Since October 1985, under CRWQCB supervision, TRW has been operating a system to pump out contaminated ground water on its site, treat it on-site in an air stripper, and discharge the treated water to Calabasas Creek and South San Francisco Bay.
Status (February 21, 1990): TRW Microwave, Signetics, and Advanced Micro Devices, Inc. (AMD) have formed a group known as "The Companies" to clean up the contaminated commingled plume. They are operating a system to pump and treat the plume with an air stripper and carbon adsorption unit at AMD's Building 915 site.
The Companies are conducting a remedial investigation/feasibility study (RI/FI) to determine the type and extent of contamination and identify alternatives for remedial action at the AMD, Signetics, and TRW sites. AMD is conducting a separate RI/FS for its Building 915 site.
For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at http://www.atsdr.cdc.gov/toxfaq.html or by telephone at 1-888-42-ATSDR or 1-888-422-8737.