Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
Sharpe Army Depot
EPA #: CA8210020832
County: San Joaquin
City: 1.5 miles east of Lathrop
Congressional District: 11
The Third Five Year Review Report was completed on September 30, 2014, and may be reviewed in the Documents and Reports section below..
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Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 10/15/84
Final Date: 07/22/87
The 724-acre Sharpe Army Depot site is a Defense Logistics Agency facility that has been involved in the storage, shipping, packaging, and maintenance of general supplies for the Department of Defense. Between 1941 and 1975, maintenance of aircraft, vehicles, industrial equipment, and medical equipment resulted in the generation of a variety of chemical wastes produced on site were disposed of in multiple locations, including the South Balloon Area, the Burning Pits Area, and the North Balloon Area. The wastes include sludge containing phenols, polychlorinated hydrocarbons, and used paints and solvents. Wastes have contaminated both soil and groundwater. All maintenance activities have ceased, and the waste areas no longer are used. The Depot employs approximately 1,200 people. The contaminated sole source aquifer supplies water to approximately 33,600 people within 3 miles of the facility. The San Joaquin River is 2 miles from the Depot.
Contaminants and Risks
- Soil and Sludges
Groundwater and soil contain volatile organic compounds (VOCs) including trichloroethylene (TCE). Soil contains metals and pesticide contamination. People who accidentally ingest contaminated groundwater or come in direct contact with site contaminants may be at risk.
Investigation and Cleanup Activities
This site is being addressed in three stages: immediate actions and two long-term remedial phases focusing on cleanup of the entire site and groundwater cleanup.
Immediate actions: Environmental studies have been underway at Sharpe since 1980. The Army initiated an interim groundwater extraction and treatment system to remove VOCs at the South Balloon Area in early 1987. A second interim groundwater treatment system became operational in the North Balloon area in late 1990. A Removal Action for pesticides in soil has been completed.
Groundwater: The Operable Unit One (OU1) Record of Decision (ROD) for treatment of VOCs in groundwater was signed in 1993. The Central Area system began operation in 1995. Additional extraction wells were added in 2014 and 2015 to optimize the cleanup.
An Explanation of Significant Differences was signed in September 2014, enhancing the groundwater remedy by adding in situ treatment and Land Use Controls (LUCs) on government property.
Soils: A ROD Amendment for Operable Unit Two (OU2) was signed in 2011 to enhance the selected remedies by adding
LUCs and burrowing owl monitoring.
Entire Site: A final base-wide ROD was signed in March 1996. Soils and soil vapor were designated as OU2. The ROD included excavations and disposal of soils contaminated with metals and soil vapor extraction for several areas of VOC contaminated soils. Soil Vapor Extraction (SVE) operated at various sites between 1998 and 2001. Another soil vapor extraction system operated from 2010 to 2014, and is currently shut down for a rebound study.
The Sharpe Army Depot is participating in the Installation Restoration Program, a specially funded program established by the Department of Defense (DOD) in 1978 to identify, investigate, and control the migration of hazardous contaminants at military and other DOD facilities.
Cleanup Results to Date
The 3 Groundwater extraction and treatment systems are constructed and operating effectively. Several soil vapor extraction systems have been operated to address VOCs, and excavation and off-site disposal of lead and chromium contaminated soil was completed. A Removal Action was completed for a small area of pesticides contamination.
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.
In 1989, the Army (as the lead federal agency) signed a Federal Facilities Agreement with EPA and State Agencies. In 1990, the Defense Logistics Agency (DLA) became the lead federal agency at Sharpe through a memorandum of agreement. In 2013, DLA relinquished its permit with the Army to use and occupy Sharpe, and as of October 2014, the lead federal agency role has been transitioned from DLA back to the Army.
Documents and Reports
|07/26/11||Proposed Plan to Enhance Groundwater Remedy|
|01/25/93||Record of Decision for OU1|
|03/05/96||Record of Decision for OU2|
|09/27/11||Record of Decision Amendment for OU2|
|09/01/14||Explanation of Significant Differences to the Record of Decision for OU1|
|06/27/03||Preliminary Close Out Report|
|01/12/04||First Five Year Report Review Report|
|09/24/09||Second Five Year Review Report|
|09/30/14||Third Five Year Review Report|
Public Information Repositories
The public information repositories for the site are at the following locations:
DDJC - Tracy, Building 1
25600 South Chrisman Road
Tracy, CA 95376-5000
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
Sacramento Field Office
8800 Cal Center Drive
Sacramento, CA 95826-3200
Environmental Support Manager
Bldg 2264, Rm 126, (ATTN: Mr. Eldridge)
Fort Sam Houston, TX 78234-7664
After Hours (Emergency Response)