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Pacific Southwest, Region 9: Superfund

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

San Gabriel Valley (all Areas)

EPA #: CAD980818579

State: California(CA)

County: Los Angeles


Congressional District: 00

Other Names:

Bulletin Board

Here is the January 2014 San Gabriel Valley Ground Water Cleanup Progress Report.SGV 1_14.pdfSGV 1_14.pdf

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Description and History

NPL Listing History

NPL Status: Final

Proposed Date: 09/08/83

Final Date: 05/08/84

Deleted Date:

The San Gabriel Valley Superfund sites include multiple areas of contaminated groundwater in the 170-square-mile San Gabriel Valley. The contaminated areas underlie significant portions of the cities of Alhambra, Arcadia, Azusa, Baldwin Park, Industry, Irwindale, El Monte, La Puente, Monrovia, Rosemead, South El Monte, and West Covina. The groundwater contamination was first detected in 1979. Following this discovery, the California Department of Health Services (CDHS) initiated a well sampling program to assess the extent of contamination. By 1984, when EPA added four areas of contamination to the National Priorities List (NPL), 59 wells were known to be contaminated with high levels of volatile organic compounds (VOCs).

The San Gabriel Basin aquifer is a critical source of drinking water for Southern California. Despite the contamination, the Valley’s groundwater continues to provide approximately 90 percent of the drinking water used by San Gabriel Valley businesses and residents. EPA’s Superfund projects are assisting in restoring water supplies that have been affected by the contamination. Additional projects have been funded by Federal grants, local assessments on water sales, and water rates.

Four areas of groundwater contamination have been listed in the National Priorities List (NPL). They are known as: San Gabriel Valley Area 1. San Gabriel Valley Area 2, San Gabriel Valley Area 3, and San Gabriel Valley Area 4.

Cleanup projects ("Operable Units") are underway in each of the four areas. In San Gabriel Vally Area 1 there are the El Monte, Richwood, South El Monte, Suburban Water Systems, and Whittier Narrows Operable Units. In San Gabriel Valley Area 2, there is the Baldwin Park Operable Unit. In San Gabriel Valley Area 3, there is the Alhambra Operable Unit. In San Gabriel Valley Area 4 there is the Puente Valley Operable Unit.

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Contaminants and Risks

Contaminated Media
  • Groundwater
  • Soil and Sludges

Groundwater contaminants include volatile organic compounds such as perchloroethylene (PCE) and trichloroethene (TCE), perchlorate, 1,4-dioxane, and N-nitrosodimethylamine (NDMA).

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Who is Involved

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Investigation and Cleanup Activities

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Cleanup Results to Date

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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.

More than one hundred facilities are believed to have contributed to the contamination through improper handling and disposal of chemicals.

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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:

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
Bella Dizon
Wayne Praskins
Raymond Chavira
Rachelle Thompson
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Viola Cooper
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
State Contact

Kate Burger


California Department of Toxic Substances Control
8800 Cal Center Drive
Sacramento, CA 95826
PRP Contact
Community Contact
Other Contacts
After Hours (Emergency Response)
(800) 424-8802

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