Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
San Gabriel Valley Area 3
EPA #: CAD980818579
County: Los Angeles
City: Alhambra, Rosemead, San Gabriel, San Marino, South Pasadena, and Temple City
Congressional District: 31
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Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 09/08/83
Final Date: 05/08/84
The San Gabriel Valley Area 3 Superfund Site (Area 3) is one of four Superfund Sites in San Gabriel Valley. Area 3 (formerly identified as the Alhambra Operable Unit) includes an approximate area of 19-square-miles containing intermittent areas of groundwater contamination. Area 3 comprises portions of the cities of Alhambra, Rosemead, San Gabriel, San Marino, South Pasadena, and Temple City.
Contamination from volatile organic compounds (VOCs) was first detected in 1979 in the San Gabriel Ground Water Basin (San Gabriel Basin) within the Valley County Water District, when Aerojet Electrosystems in Azusa sampled wells. Hundreds of individual facilities in the San Gabriel Basin could have contributed to the contamination in the basin through improper chemical handling and disposal practices.
EPA currently is working on a supplemental Remedial Investigation and a Feasibility Study (FS) of regional groundwater contamination in Area 3 to identify and evaluate cleanup options. The Remedial Investigation assessment involved facility investigations in cooperation with the California Regional Water Quality Control Board, Los Angeles Region (RWQCB) as part of an effort to identify Potentially Responsible Parties (PRPs - companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site) and associated sources of groundwater contamination. EPA's review of investigation data and historical records was used to identify PRPs.
Contaminants and Risks
- Soil and Sludges
Ground water in Area 3 is contaminated with VOCs, including trichloroethylene (TCE) and tetrachloroethylene (PCE), at concentrations that exceed 20 times the maximum contaminant levels (MCLs) allowed by federal and State law. Soil also is contaminated with various VOCs . People who inhale vapors from groundwater or soil that contains VOCs could be exposed to hazardous substances.
All drinking water served within Area 3 meets federal and State drinking water standards. While EPA works to identify possible regional groundwater contamination in Area 3, the State is working with facilities to address soil contamination.
Investigation and Cleanup Activities
Ground water contamination in Area 3 is being addressed in two long-term remedial phases focusing on cleanup of area-wide identification and contamination and control of the sources of contamination.
Area-wide Contamination: In 1984, EPA began a study of the nature and extent of contamination throughout the San Gabriel Basin. This investigation identified specific areas within the San Gabriel Valley Superfund Sites for focused study and for further support of ongoing activities. This investigation led to additional required groundwater cleanup or monitoring in specific operable units in the San Gabriel Valley All Areas.
Source Identification and Control: RWQCB is identifying sources of contaminants in San Gabriel Valley Area 3.
Remedial Investigation: EPA started the Remedial Investigation (RI) for Area 3 in 1999, including the collection of extensive data over a seven year period. The RI report, completed in June 2009, assesses the nature and extent of groundwater contamination in Area 3 and the potential for harm to public health or the environment caused by the contamination. EPA will perform a supplemental RI to assess the presence of regional groundwater contamination. Conclusions of the supplemental RI will form the basis of a Feasibility Study (FS) to evaluate cleanup alternatives to prevent and eliminate the release or the threat of release of contaminants in groundwater at the site.
Feasibility Study: The next step in the Superfund process will involve completing a FS for Area 3 to develop, screen and evaluate cleanup alternatives. Potential cleanup alternatives may focus on preventing and eliminating the release or the threat of release of contaminants at the site. During development of the FS, EPA is collecting additional data to address remaining uncertainties identified in the RI.
The San Gabriel Valley Oversight Group will use the Technical Assistance Services for Communities (TASC) to provide a public-driven assessment of groundwater contamination data and other cleanup information that is independent of federal, State, and municipal agencies and to conduct community outreach.
Cleanup Results to Date
After adding the San Gabriel Valley Area 3 Site to the NPL in 1984, EPA confirmed through preliminary investigations that no immediate actions are required while studies are ongoing and potential cleanup actions are under evaluation. Currently, all drinking water served within Area 3 meets federal and State drinking water standards. EPA conducted additional investigations to identify PRPs responsible for contamination of the groundwater within Area 3 and to support evaluation of cleanup alternatives.
Since 2003, EPA has installed eight groundwater monitoring wells and conducted routine groundwater sampling to evaluate groundwater contamination. EPA's RI report assessed water quality data collected from these wells, along with data collected from monitoring wells installed at over 10 facilities under investigation in Area 3 and from production wells throughout Area 3. The report also includes a site conceptual model that will help EPA to evaluate cleanup alternatives. EPA is now working on a supplemental remedial investigation and a feasibility study to identify and evaluate cleanup alternatives.
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.
Documents and Reports
Public Meetings: Public Meetings:
- EPA had a Community Open House on October 3, 2002, describing the Superfund process and the monitoring well installation project. Please see "EPA to begin field work to investigate groundwater quality in Alhambra" document in the Fact Sheets section above for more details.
Informational Workshops were held on August 10, 2005, and August 13, 2005, where EPA sought community feedback for the remedial investigation and cleanup process. Please refer to the "Information Workshop" document in the Fact Sheets section above for more information.
The last public meeting was held in the spring of 2010.
Public Information Repositories
The public information repositories for the site are at the following locations:
Alhambra Civic Center Library
101 South First Street
Alhambra, CA 91801
8800 Valley Boulevard
Rosemead, CA 91770
West Covina Library
1601 West Covina Parkway
West Covina, CA 91790
EPA Site Manager
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
Curt M. Charmley,
California Regional Water Quality Control Board-Los Angeles Region
320 W. 4th Street
Los Angeles, CA 90013
Alhambra, CA 91801
After Hours (Emergency Response)