Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
EPA #: CAD000074120
Congressional District: 01
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Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 12/30/82
Final Date: 09/08/83
The MGM Brakes Superfund site is an approximately 5-acre area located in Sonoma County in the southern portion of the City of Cloverdale, California. The site is located at the southwest corner of the intersection of Donovan Road and South Cloverdale Boulevard. Cloverdale is an agricultural community of approximately 4,500 residents. Runoff from the site drains into Icaria Creek, which is a tributary to the Russian River. The Russian River is approximately 1 mile east of the site. The groundwater aquifer underlying the site is used as a public drinking water source. Water is provided by the South Cloverdate Water Company and is collected from two wells located one-half to three-quarter miles upgradient and to the east of the Site. No downgradient water supply wells have been identified.
From 1962 until operations ceased in 1982, the MGM Brakes facility manufactured and cast aluminum brake components for large motor vehicles. The facility consisited of a casting plant building, seven above ground tanks, a cooling tower, and a storage shed. From 1965 until 1972, hydraulic fluids containing polychlorinated biphenyls (PCBs) were used in the casting machines. These hydraulic fluids leaked from the casting machines in the normal course of plant operations and were then collected, together with water used to cool the dies between castings, in floor drains. Following gravity separation of oils and grease, the wastewater containing PCBs was discharged, via a drain line, to the ground adjacent to the casting plant. The use of hydraulic fluid containing PCBs was gradually discontinued in 1973, but wastewater containing ethylene glycol (the hydraulic fliud later used in the casting machines) continued to be discharged in the same manner until 1981. The practice of discharging wastewater onto the vacant fields surrounding (mostly to the south) of the casting plant building is believed to be the main cause of contamination at the site.
On August 11, 1981, the North Coast Regional Water Quality Control Board (NCRWQCB) conducted a site inspection in response to a citizen complaint. During the inspection they noted the presence of oily soil. The soil was found to be contaminated with PCBs. The State ordered the company to stop all discharge activity and to investigate the nature and extent of contamination. The owners of the site, TBG, Inc. and Indian Head Industries, Inc. conducted additional sampling under state oversight from 1981 to 1983. PCB contamination was detected in surface water runoff, surface and subsurface soil, and inside the casting plant building. In 1986, volatile organic compounds (VOCs) were detected in groundwater at the northeastern and southeastern boundary of the MGM Brakes property and in groundwater on parcels 62 and 63 immediately adjacent to the northeastern and southeastern boundary of the property. The detected VOCs were benzene, chlorobenzene, cis-1,2-dichloroethylene, 1,4-dichlorobenzene, 1,1-dichloroethylene, 1,1,1,-trichloroethane, trichloroethylene, and vinyl chloride.
EPA assumed lead agency responsibility for oversight of site investigation and cleanup activities in 1983 when the site was added to the National Priorities List. All demolition and cleanup activies described below in the section titled "Cleanup Approach" have been completed. A Voluntary Covenant and Agreement to restrict use of certain portions of the site was recorded in Sonoma County in July 1995. Groundwater was sampled on a semi-annual basis to monitor the progress of natural attenuation until October 2013 when groundwater contamination was below maximum contamination levels (MCLs) for all contaminants of concern.
Contaminants and Risks
Contamination is below maximum contamination levels for all contaminants of concern.
Who is Involved
This site is being addressed through Federal, State, and potentially responsible parties' actions.
From 1983 to 1988, the owners of the site conducted a Remedial Investigation and Feasibility Study under EPA and State oversight. In September 1988, EPA issued a Record of Decision (ROD) which selected excavation and off-site disposal of PCB contaminated soils above 10 parts per million (ppm), demolition of the casting plant and decontamninaiton of PCB contaminated equipment and materials. For groundwater, the ROD included activities to locate the source of VOCs, installation of additional wells to evaluate the extent of VOC contamination and groundwater monitoring.The ROD provided for development and implementation of additional remedial measures, if warranted, to ensure that groundwater was restored to Safe Drinking Water Standards, known as Maximum Contaminant Levels (MCLs).
In May 1990, a Remedial Design/Remedial Action Consent Decree was entered into by EPA and the site owners, TBG Inc. and Indian Head Industries, Inc. in which they agreed to design and construct the remedy and pay past costs for cleaning up the site.
While conducting the excavation work (more than 900 grid squares werre identified for excavation) some bedrock was encountered that required modification of the 1988 ROD. In August 1995, EPA issued an Explanation of Significant Difference (ESD) which revised the ROD by allowing soil that contained less than 100 ppm of PCBs and located at least 15 feet below ground surface to be left in place due to the impracticability of removal.The result of this action was that in 11 grid squares (12.5 feet by 12.5 feet) the remedial goal for PCB was not met. These grid locations can be found in Appendix F to the First Five-Year Review for MGM Brakes and in the Voluntary Covenant and Agreement to restrict land use filed with Sonoma County.
The ESD also selected monitored natural attenuation (MNA) as the groundwater remedy and defined a Point of Compliance (POC). The POC was to be used to ensure that contaminants did not move beyond the boundary line (the POC) at concentration levels greater than MCLs. Groundwater was sampled on a semi-annual basis until October 2013 to monitor the progress of MNA when groundwater contamination was below maximum contamination levels for all contaminants of concern.
The Third Five-Year Review was published on September 26, 2013. Like the First and Second Five-Year Reviews, the Third Five-Year Review found the remedy to be protective of human health and the environment because all exposure pathways have been eliminated or controlled.
Cleanup Results to Date
Cleanup of soil is complete. Groundwater is sampled on a semi-annual basis to monitor the progress of natural attenuation. Only one well remains slightly above the safe drinking water standard for TCE.
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.
The PRPs are TBG Inc. and Indian Head Industries, Inc.
Documents and Reports
Public Information Repositories
The public information repositories for the site are at the following locations:
Sonoma County Public Library,
3rd and E Streets,
Santa Rosa, CA 95404
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
5550 Skylane Blvd., Suite A
Santa Rosa, CA 95403
1870 Ogden Drive
Burlingame, CA 94010
After Hours (Emergency Response)