applied materials

3050 BOWERS AVE

The site was constructed in about 1970 and is located at 3050 Bowers Avenue, a light industrial and commercial area of Santa Clara. A large industrial building occupies most of the site. Most buildings in the vicinity are low-rise developments containing office space and research and development facilities. The facility has been used to manufacture equipment for the fabrication of semiconductor wafers from 1974 to the present. During the 1970s, Volatile Organic Compounds (VOCs) were used as industrial solvents for cleaning and degreasing. Acids, caustics, and other chemicals were also used at the facility. The site is located in the Santa Clara Valley, a structural basin filled with marine and alluvial sediments. The natural groundwater flow direction beneath the site is to the north towards San Francisco Bay. Municipal water supply wells tap an extensive, deep, regional, confined aquifer that lies generally greater than 200 to 300 feet below ground surface (bgs). Groundwater at the site is contaminated with Volatile Organic Compounds (VOCs), primarily of 1,1,1-trichloroethane (1,1,1-TCA), 1,1-dichloroethane (1,1-DCA), and 1,1-dichloroethene (1,1-DCE). In November 1983, VOCs were discovered in a monitoring well down gradient from three Underground Storage Tanks (USTs) on the west side of the large building. Site investigation began shortly after the contamination was discovered. Groundwater monitoring and extraction wells were installed and groundwater extraction began in November 1984. In January 1985, Applied Materials removed the tanks, excavated the contaminated soils, and constructed a groundwater extraction pit. The site overlies the Santa Clara Valley groundwater basin. Groundwater from this basin provides up to 50% of the municipal drinking water for over 1.4 million residents of the Santa Clara Valley. The site became a Superfund site primarily because of the past chemical releases' potential threat to this valuable groundwater resource.