Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
Jasco Chemical Corp.
EPA #: CAD009103318
County: Santa Clara
City: Mountain View
Congressional District: 14
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Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 06/24/88
Final Date: 10/04/89
The Jasco Chemical Company Superfund Site (JASCO) consists of the property located at 1710 Villa Street in Mountain View, CA. JASCO repackaged and formulated chemical products on the 2.05 acre Villa Street site from 1976 until December 1995. Bulk solvents used at the site were received by tankers and stored in eight underground storage tanks. Prior to 1985, Tank #3 was used to store pentachlorophenol (PCP), which was an ingredient of a wood preservative formerly produced by Jasco. The product was discontinued in 1985, and the tank was converted to store paint thinner. Elevated levels of volatile organic compounds (VOCs) were detected in soils from a swale area located behind the building and in the shallow groundwater. Past waste disposal practices, and possibly leakage from an underground storage tank and surface water, may have contributed to soil and groundwater contamination. The City of Mountain View has a total population of approximately 62,000. The only surface water body within one mile is Permanente Creek. Approximately 330,000 people within three miles of the site depend on groundwater for drinking water. In 1987, the City of Mountain View shut down one well near the site to determine whether site activities would affect the well. In 1988, after the investigations revealed that contamination had not migrated into the groundwater for this well, it was placed back into operation.
This site has been in the Operation and Maintenance phase since 2002 when the remedy was determined to be functionally complete. The groundwater was sampled annually until 2011.
Contaminants and Risks
- Surface Water
- Soil and Sludges
Groundwater is contaminated with VOCs, PCPs, and diesel fuel. Soil contained VOCs and diesel fuel. People's health may be adversely affected if they inhale contaminated vapors, or drink or come in direct contact with contaminated water.
Who is Involved
This site is being addressed through Federal and potentially responsible parties' actions.
Investigation and Cleanup Activities
This site is being addressed in two stages: initial actions and a long-term remedial phase focusing on cleanup of the entire site.
Initial Groundwater Cleanup
Jasco installed groundwater monitoring wells, took soil samples, and removed some contaminated soil. In early 1987, Jasco began extracting and discharging groundwater from an on-site well into the city sewer system. The levels of VOCs in the groundwater were low enough to meet city sewer system requirements.
One soil stockpile generated from the underground storage tank excavation project contained PCP at a concentration of 260 ppm, which was above the cleanup standard of 200 ppm. Approximately 35 cubic yards of contaminated soil from the stockpile were treated on site using an ex-situ biotreatment process. This process was an engineered design with combined ex-situ bioventing and fungal-based bioremediation technology to remediate the soil. The biotreatment cell was constructed and operated from September 1997 through March 1998. Confirmation sampling has shown that cleanup levels had been reached successfully in this area.
Long-term Groundwater Cleanup
In early 1991, the potentially responsible party, under EPA supervision, completed investigations into the nature and extent of groundwater contamination at the site. Treatability studies for soil cleanup were completed and, in 1992, a cleanup remedy was selected to address site contamination. During the winter of 1994, EPA approved the installation of a pilot-scale dual vacuum extraction (DVE)/soil vapor extraction (SVE) system for the drainage swale area of the site. The purpose of this pilot test was to evaluate DVE/SVE as a remedy for cleanup of the soil and groundwater. The pilot-scale system started operating in 1995. In April of 1997, in response to the appearance of PCE in groundwater near the southeastern corner of the warehouse facility, JASCO voluntarily converted a monitoring well to DVE. After later sampling activities identified a shallow perched water-bearing zone above the A-aquifer in this area, JASCO constructed a second DVE well, screened within the perched zone, in October of 1997. These wells were installed to remove PCE from the water table and shallow soil and to limit further migration of PCE in groundwater. The expanded DVE system remained in operation until April of 1998, when an expanded groundwater extraction and treatment system was constructed. EPA and the Regional Water Quality Control Board (RWQCB) conducted an analysis and have concluded that JASCO is not the source of this PCE contamination. Thus, JASCO will not be held responsible for cleaning up this PCE plume. As a result, the groundwater must stay restricted until such time the appropriate authorities are able to address this non-related PCE contamination.
The groundwater treatement system operated until September 2002. At that time, it was determined that the groundwater Jasco was responsible for cleaning up had met the cleanup requirements set forth in the Record of Decision. The groundwater has been monitored regularly to ensure that the remedy remains protective.
Additional investigative work, however, will be required to further investigate the PCE plume that has migrated onto the Jasco property, to ensure that risks posed by this newly identified groundwater plume are minimal.
Homes may be built at the site. In order to determine if it would be safe to do so, soil vapor samples were collected on site by the PRP (Nov. 2002) and a draft Human Health Risk Assessment for PCE in Soil and Soil Vapor (Jan. 2003) was prepared for the City of Mountain View Planning Department to assess the risk to future construction workers and residents. EPA has reviewed this risk assessment and provided comments. Redevelopment activities will not occur until the City of Mountain View has been assured that the construction plans are protective of human health and the environment. As far as the PCE is concerned, EPA's Site Assessment Team is investigating the source of this contamination. A meeting was held with the City of Mountain View, the Regional Water Quality Control Board, and the Santa Clara Valley Water District to discuss how our agencies can address this PCE issue.
An Explanation of Significant Differences (ESD) was finalized on September 13, 2002. This ESD modified the treatment method for groundwater, the treatment method for soil in the drainage swale area at the rear of the JASCO facility, and the deed restriction requirement. The groundwater remedy was modified to utilize an air stripper and vapor-phase carbon adsorption treatment in order to meet more stringent National Pollutant Discharge Elimination System (NPDES) permit requirements which were not in place when the ROD was implemented. The soil in the drainage swale area was treated using an alternative method since excavation so close to the railroad tracks would not have been feasible. The deed restriction identified in the ROD is being adjusted to reflect that the groundwater at the JASCO site has been subsequently impacted by an off-site source of PCE contamination.
Jasco reached construction completion on September 20, 2002. A preliminary closeout report (PCOR) documented that the construction of the cleanup remedy was complete.
Five Year Review
EPA completed a five-year review at the JASCO Chemical Company Superfund Site in Mountain View, CA in September 2007. This review summarized cleanup activities that have taken place and evaluated whether the selected remedy remains protective of human health and the environment. According to Superfund law, if a cleanup action takes more than five years to complete and/or leaves waste in place, the protectiveness of the remedy will be reviewed every five years.
The review determined that the remedy performed as designed, and that the remedy is protective of human health and the environment. The review recommended further investigations into the source and extent of a PCE plume that has migrated onto JASCO property from an off-site source, and coordinating with state-led investigations. The results of this review are available below.
A new PCE plume was discovered in 1993. (This plume is separate and distinct from JASCO's contamination plume which contained a mixture of PCE, methylene chloride, diesel, etc.) Extensive research was carried out by the PRPs which showed that the PCE originated from an off-site source. EPA agrees with this conclusion. Thus, JASCO is not responsible for cleaning up this PCE plume. However, the PRPs will be held responsible for making sure this new PCE plume will not adversely impact redevelopment of the site. They will be required to put a deed restriction in place that will prevent the migration of chemicals through the vapor intrusion pathway and continue to restrict the use of contaminated groundwater as drinking water.
Cleanup Results to Date
The removal of contaminated soil, the operation of the groundwater extraction system, and the use of the DVE/SVE system have reduced the potential of exposure at the Jasco Chemical Co. site. Results from soil confirmation samples, collected on February 26, 2002, have shown that the site soils have reached cleanup goals. The groundwater treatment system has been shut off after confirmation that the contaminated groundwater plume at the Jasco site has been remediated to cleanup standards.
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 Information Repositories
The public information repositories for the site are at the following locations:
Mountain View Public Library
585 Franklin St.,
Mountain View, CA 94041
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
After Hours (Emergency Response)