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Pacific Southwest, Region 9: Superfund

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

Teledyne Semiconductor

EPA #: CAD009111444

State: California(CA)

County: Santa Clara

City: Mountain View

Congressional District: 14

Other Names:

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: 10/15/84

Final Date: 07/22/87

Deleted Date:

Teledyne Semiconductor has operated as a semiconductor manufacturer at this 1-acre site since 1962. In 1982, Teledyne reported to the California Regional Water Quality Control Board (CRWQCB) that soil and groundwater were contaminated with solvents from an underground solvent storage tank. The State inspected the site and found that contaminants had migrated north of the site and affected approximately 50 private domestic wells. Furthermore, contaminated groundwater that migrated north from another NPL site, Spectra-Physics, Inc., merged with the contaminated plume of the Teledyne site. The two firms are cleaning up the sites jointly. These sites are among the 28 sites in the South Bay Area of San Francisco. Facilities at these sites have used a variety of toxic chemicals, primarily chlorinated organic solvents, which have contaminated a common groundwater basin. Although the sites are listed separately on the NPL, the EPA intends to combine cleanup activities at some of the sites as part of an area-wide approach to the contamination. The site is located in a densely populated, urban area. Approximately 189,000 people live within a 3-mile radius of the site. The distance from the site to the nearest residence is 200 feet.

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Contaminants and Risks

Contaminated Media
  • Groundwater
  • Soil and Sludges

Soil was contaminated with volatile organic compounds (VOCs). Groundwater is contaminated with VOCs. Drinking water is not affected by this contamination. Drinking water for this area comes from the Hetch Hetchy Reservoir in the Sierra Nevada, not from regional groundwater.

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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

Cleanup Ongoing

Entire Site: In 1990, the EPA selected the following cleanup remedies: excavation and removal of contaminated soil; groundwater extraction and treatment through an air stripper; and quarterly monitoring of the groundwater, as well as the soil. All soil excavation is complete at the site. Groundwater treatment will continue until established cleanup goals are met.

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Cleanup Results to Date

Construction of all cleanup remedies is complete. Contaminated soil has been removed. Ongoing extraction and treatment of the groundwater continues to reduce the potential for exposure to contaminants at the Teledyne Semiconductor site. Groundwater treatment will continue until established cleanup goals are met.

The Third Five-Year Review for the site was completed in September 2009, and in the Spring Street and North Bayshore areas, the vapor intrusion exposure pathway is currently being evaluated. An addendum to the 2009 Five Year Review is required.

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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

Hide details for Community InvolvementCommunity Involvement
01/01/14Residential Indoor Air Sampling Outreach Letter
05/01/14Sample Letter (VI Requiring Mitigation) - Indoor Air Sampling Results for Residential Building #XX, Mountain View, California
05/01/14Sample Letter (VI Under Screening Levels) - Indoor Air Sampling Results for Residential Building #XX, Mountain View, California
Hide details for Fact SheetsFact Sheets
12/01/13South Bay Groundwater Sites - Vapor Intrusion Evaluations (Dec. 2013 Update)
04/01/14Vapor Intrusion Mitigation Fact Sheet
Hide details for MapsMaps
08/30/10Site Map Showing Groundwater TCE Isoconcentrations - Commercial
01/08/14Site Map Showing Residential Buildings and the Underlying Contamination Area (Included In The Work Plan Addendum)
03/20/14Vapor Intrusion Study Area Map
Hide details for Records of DecisionRecords of Decision
03/22/91Record of Decision
Hide details for Technical DocumentsTechnical Documents
09/29/99First Five Year Review Report
09/30/04Second Five Year Review Report
09/30/09Third Five Year Review Report
12/03/13EPA Region 9 Guidelines and Supplemental Information Needed for Vapor Intrusion
Evaluations at the South Bay National Priorities List (NPL) Sites - Letter
02/19/14Approval of Work Plan Addendum for Vapor Intrusion Evaluation of Residential Buildings in the Off-Property Study Area - Letter
05/24/14Data Summary for Residential Indoor Air Sample Results (May 2014)
06/16/142Q Vapor Intrusion Evaluation Progress Report
07/09/14EPA Region 9 Response Action Levels and Recommendations to Address Near-Term Inhalation Exposures to TCE in Air from Subsurface Vapor Intrusion
09/23/144th Five-Year Review Report
10/02/14Site-Wide VI & GW Investigative/Remedial Path Forward: Minutes of October '14 meeting bewtween EPA, RPs & the State
10/21/14Work Plan Addendum for Vapor Intrusion Evaluation of the Former Teledyne Semiconductor Building Located at 1300 Terra Bella Avenue,
04/30/15First Quarter 2015 - Vapor Intrusion Evaluation Data Submittal for the FormerTeledyne Semiconductor and Spectra-Physics Lasers, Inc., Sites
05/22/15Soil Vapor Extraction System Construction Completion Report and Operations and Maintenance (O&M) Schedule

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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:

Mountain View Public Library
585 Franklin Street
Mountain View, CA 94041

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
Roger Papler
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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