Superfund Information Systems: Site Profile

Superfund Site:


Health & Environment

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What Are the Risks at the Site?

Your drinking water is not affected by contamination associated with the Site. Drinking water is supplied by the City of Mountain View and comes from sources such as the Hetch Hetchy Reservoir in the Sierra Nevada Mountains. This public water supply is regularly tested to ensure that it fully meets all state and federal drinking water standards.

´╗┐Vapor intrusion risks are currently under evaluation. During the past few years of indoor air testing, over 450 samples were collected from 16 commercial buildings and 31 residential buildings. At the majority of buildings, vapor in-trusion was either not detected or detected at very low levels that do not pose a health risk. A small number of homes and some businesses required additional monitoring or cleanup work to address potential risk, this work is still ongoing.   If you live in the Indoor Air Sampling Study Area, shown on the fact sheet Figure 3, and would like to participate in the sampling, please contact Angela Sandoval, P.E., Project Manager, at (415) 972-3831 or by email to You may also contact Alejandro Diaz, EPA's Community Involvement Coordinator, who is fluent in Spanish, at (415) 972-3242 or by email to


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Contaminant Information

Groundwater beneath the Site has been impacted by a group of chemicals called volatile organic compounds (VOCs), primarily the chemical trichloroethene or TCE. TCE was used at the Site Semiconductor and Spectra-Physics properties decades ago in semiconductor and other electron-ics manufacturing operations. During these activities, TCE was inadvertently released to the environment and impacted the groundwater beneath the properties. TCE-containing groundwater from the two properties mixed together and traveled north past Highway 101, where it mixed with contamination from certain other sources. See https:// for more information on nearby source areas. Before the releases were found and the groundwater cleanup system was put in place, the contamination traveled approximately one mile to the north and northwest.

View a full list of contaminants of concern for this site.

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Performance Measures

EPA uses performance measures to track environmental results at Superfund sites. If you have any questions or concerns about the measures at this site, please contact the site team members listed under Site Contacts.

Read more about Superfund Remedial Performance Measures.

Status at this
Superfund Site
What does this mean?
Human Exposure Under Control Yes Yes means assessments indicate that across the entire site:
  1. There are currently no unacceptable human exposure pathways; and
  2. EPA has determined the site is under control for human exposure.

No means an unsafe level of contamination has been detected at the site and a reasonable expectation exists that people could be exposed.

Insufficient data means that, due to uncertainty regarding exposures, one cannot draw conclusions as to whether human exposures are controlled, typically because:
  1. Response to the contamination has not begun; or
  2. The response has begun, but it has not yet generated information sufficiently reliable to evaluate whether there are currently any unacceptable human exposure pathways at the site.
Groundwater Migration Under Control Yes

Yes means EPA reviewed all information on known and reasonably expected groundwater contamination. EPA concluded the migration of contaminated groundwater is stabilized and there is no unacceptable discharge to surface water. EPA will conduct monitoring to confirm that affected groundwater remains in the original area of contamination.

No means EPA has reviewed all information on known and reasonably expected groundwater contamination, and the migration of contaminated groundwater is not stabilized.

Insufficient data means that due to uncertainty regarding contaminated groundwater migration, EPA cannot draw conclusions as to whether the migration of contaminated groundwater is stabilized.

Construction Complete Yes

Yes means the physical construction of the cleanup is complete for the entire site.

No means either physical construction is not complete or actions are still needed to address contamination.

Sitewide Ready for Anticipated Use No Yes means:
  1. All cleanup goals affecting current and reasonably anticipated future land uses of the entire site have been achieved, so there are no unacceptable risks;
  2. All required land-use restrictions or other controls have been put in place; and
  3. The site has achieved Construction Complete status.

No means that one or more of these three criteria have not been met. However, a site listed as no may still have redevelopment occurring on portions of the site and may be eligible for additional redevelopment.

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