Background

EPA began investigating groundwater in the area in the 1980s. The investigation found three manufacturing facilities—AMD, TRW Microwave, and Signetics—had contaminated the groundwater. Since 1982, the contaminated groundwater has been contained and treated. Treatment work is ongoing.

In August 2014 the State of California, San Francisco Bay Regional Water Quality Control Board (Regional Board) transferred the agency oversight role for the Triple Site back to EPA Region 9. The "Triple Site" is the collective name for three adjacent sites in Sunnyvale that have jointly contributed to a groundwater solvent plume. The sites were transferred back to EPA Region 9 as part of an effort ...
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