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Pacific Southwest, Region 9: Superfund

Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations

TRW Microwave, Inc. (Building 825)

EPA #: CAD009159088

State: California(CA)

County: Santa Clara

City: Sunnyvale

Congressional District: 14

Other Names: Aertech Industries FEI

Bulletin Board

EPA is currently evaluating the potential for vapor intrusion in buildings overlying the shallow groundwater contamination area. On December 3, 2013 EPA sent a letter to the State of California's Regional Water Quality Control Board providing guidelines for vapor intrusion sampling and evaluation at this and 10 other South Bay State-lead sites.

Description and History

NPL Listing History

NPL Status: Final

Proposed Date: 06/24/88

Final Date: 02/21/90

Deleted Date:

The TRW Microwave, Inc. (Building 825) site neighbors three other NPL sites: Signetics, Advanced Micro Devices (AMD), and AMD #915. A groundwater plume from the four sites covers 1/3 square mile in Sunnyvale. The TRW facility was occupied by Aertech Industries from 1968 until it was sold to TRW, Inc. in 1984. In 1987, TRW sold the facility to FEI Microwave, Inc., its current occupant. The primary activity at the site was assembling and testing microwave components, until semiconductor processing began in 1970. Primarily solvents and small quantities of acids are used in the assembly areas for semiconductors. Solvents, acids, and heavy metals are used in the fabrication areas and plating shop. The paint shop uses paints and solvents. Groundwater beneath the site is contaminated with volatile organic compounds (VOCs). Acid rinse water generated by the assembly processes is neutralized on site and is discharged to the City of Sunnyvale sewer system. However, rinse water containing metals is not sent to the neutralizers; it is collected in containers and disposed of off site. An underground ammonia gas acid neutralization system was installed when the facility first opened. Floor drains and acid sinks in the plating shop were connected to buried plumbing that carried acid waste to the neutralization system. This system was closed in 1986, and the underground piping was sealed. The system was replaced with three aboveground tanks. Spent solvents were stored in one of four on-site underground tanks. Since 1983, solvents have been stored in drums and transported off site. The closest residence is located 1,200 feet north of the site. Contaminants from the site have the potential to migrate to deep drinking water aquifers. Municipal wells for the cities of Santa Clara and Mountain View tap a deep aquifer that serves approximately 300,000 people.

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Contaminants and Risks

Contaminated Media
  • Groundwater
  • Soil and Sludges

Groundwater and soil contain various VOCs. People who accidentally ingest or come in direct contact with contaminated groundwater or soils may be at risk. The deep aquifer, used as a drinking water source, is not contaminated; however, the shallow aquifer is contaminated. There are some agricultural wells that could act as conduits for contaminant migration between the shallow contaminated aquifer and the deep aquifer.

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Who is Involved

This site is being addressed through Federal, State, and potentially responsible parties' actions.

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Investigation and Cleanup Activities

Initial Actions

Initial Actions: Four spent solvent underground tanks, along with some soil, were removed in 1973, 1976, 1980, and 1983. In 1984, 120 cubic yards of contaminated soils were excavated and transported to an EPA-approved hazardous waste facility. The site was backfilled to the surface with gravel, and concrete was poured over the gravel to prevent rainwater from seeping into the pit. This water extraction pit is part of an eight-well groundwater extraction system operated by TRW. Since 1985, groundwater has been pumped from seven on-site extraction wells and the pit to prevent VOCs from migrating off site and to extract the groundwater for cleanup. On-site groundwater is treated by an air stripper and then discharged to Calabasas Creek. In addition, groundwater has been pumped from a total of 24 off-site extraction wells and conveyed through an underground piping system to the air strippers located at the AMD #915 site. Approximately 20 percent of the water is treated and then discharged to a storm drain, which empties into the Calabasas Creek. The remainder is used as process water by AMD #915.

Cleanup Ongoing

Entire Site: In 1989 under State oversight, TRW began investigating the type and extent of contamination remaining on the site. TRW completed the investigation in early 1991. The final cleanup remedy selected in late 1991 was the continuation of groundwater extraction and air stripping, which will proceed until established cleanup goals are met.

Additional in-situ enhanced bioremediation has been ongoing in an effort to reduce contaminant concentrations on the TRW Microwave site.

In 1984, the State issued an order requiring AMD, Signetics, and TRW to develop a joint plan to prevent further migration of contaminants. New orders in 1989 required TRW to submit an investigation and proposed cleanup plan with AMD and Signetics.

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Cleanup Results to Date

Construction of all cleanup remedies is complete. The removal of tanks and contaminated soil has reduced the potential for exposure to contaminated materials at the TRW Microwave, Inc. (Building 825) site while groundwater continues to be treated.

The third Five Year Review was completed in September 2009 and concluded that:
The remedy at the TRW Microwave (TRW) Superfund site in Sunnyvale, California is currently protective of human health and the environment. Enhanced Anaerobic Biodegradation process is currently being tested at the Site. In the short-term, the institutional controls are preventing exposure to, and the ingestion of, contaminated groundwater. The ROD and final SCR will be amended.

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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.

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Documents and Reports

Show details for Fact SheetsFact Sheets
Show details for Records of DecisionRecords of Decision
Show details for Technical DocumentsTechnical Documents

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Community Involvement

Public Meetings:

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Public Information Repositories

The public information repositories for the site are at the following locations:

California Regional Water Quality Control Board
1515 Clay Street
Suite 1400
Oakland, CA 94612

The most complete collection of documents is the official EPA site file, maintained at the following location:

Superfund Records Center

Mail Stop SFD-7C

95 Hawthorne Street, Room 403

San Francisco, CA 94105

(415) 820-4700

Enter main lobby of 75 Hawthorne street, go to 4th floor of South Wing Annex.

Additional Links

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EPA Site Manager
Melanie Morash
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Alejandro Diaz
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
State Contact
Max Shahbazian
California Regional Water Quality Control Board
1515 Clay Street
Suite 1400
Oakland, CA 94612
PRP Contact
Community Contact
Other Contacts
After Hours (Emergency Response)
(800) 424-8802

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