Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
Liquid Gold Oil Corp.
EPA #: CAT000646208
County: Contra Costa
Congressional District: 07
On 10/13/17, this website will no longer be updated. Site information will be migrated to the new web page at: http://www.epa.gov/superfund/liquidgold .
EPA appreciates your patience through this transition. If you have questions, please contact EPA staff listed below.
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Description and History
NPL Listing History
NPL Status: Deleted
Proposed Date: 12/30/82
Final Date: 09/08/83
Deleted Date: 09/11/96
The Liquid Gold Oil Corp. site consists of approximately 18 acres of a 29-acre property owned by Southern Pacific Transportation (SPT). Originally, a major portion of the property was marshlands, which was reclaimed in the 1940s and 1950s. SPT leased approximately 3 acres of the site to an asphalt manufacturing plant and later to a waste oil storage and transfer facility that operated under the name of Liquid Gold Oil Corporation. Improper handling and disposal practices resulted in soil contamination. In 1982, Liquid Gold Oil ceased operations and left several deteriorating buildings and 27 storage tanks of various sizes on the site. Cleanup of the site was completed in 1995, and the site was de-listed from the Superfund National Priorities List in 1996.Currently, the site is inactive and fenced. The population within a mile is approximately 7,000, and an estimated 92,000 people live within 4 miles of the site. There are public wells located within 1/2 mile of the site, and nine private wells located within 3 miles of the site.
Contaminants and Risks
- Soil and Sludges
- Environmentally Sensitive Area
Soils and groundwater are contaminated with metals and petroleum hydrocarbons. Prior to removal and capping of contaminated soils, people could be exposed to a health risk through accidental ingestion or direct contact with soils. Adjacent wetlands also may have been adversely affected by the site. However, risks have been eliminated by controlling pathways of exposure. Contaminated soils have been covered with a vegetated cap, the cap is fenced and the site is subject to a deed restriction that prohibits residential use.
Who is Involved
This site has been addressed through Federal, State, and potentially responsible parties' actions.
Investigation and Cleanup Activities
This site was addressed in two stages: initial actions and a long-term remedial phase focusing on cleanup of the entire site.
Initial Actions: In response to inspections and regulatory actions, some surface soil was removed in 1974, and liquid waste and soil from a drainage area and holding pond were removed in 1980. Twenty five storage tanks and more than 70 drums of hazardous waste were removed and disposed off-site from 1982-84. In 1985, 760 cubic yards of contaminated soil were excavated and a wooden building in the former asphalt facility removed, resulting in off-site disposal of an additional 65 cubic yards of wood and metal debris. The remaining site buildings were demolished and the debris disposed off-site in 1989.
Site Studies: Under State supervision, the potential responsible party prepared a Remedial Investigation (RI)/Feasibility Study (FS) Workplan for the site in 1988 and RI/FS activities were conducted during 1988-1992. These studies were summarized in a Remedial Action Plan (RAP), approved by the Department of Toxic Substances Control and EPA in 1993. The study results indicated elevated concentrations of lead, copper, and mercury in surface and subsurface soils. The elevated lead was found primarily in a 5-acre area in the central portion of the site. Polynuclear Aromatic Hydrocarbons (PAHs) were found in five surface soil sample located within the same 5-acre area. Oil and grease were found throughout site soils, though a source could not be identified.
Groundwater was also sampled and analyzed, and continues to be monitored. The groundwater contained elevated metals and petroleum hydrocarbons (diesel and gasoline). Ongoing monitoring indicates that contaminated groundwater is not migrating and that concentrations of contaminants are decreasing over time. Surface water samples from two drainage channels showed no surface water contamination.
An ecological risk assessment found evidence of possible ecological damage in two drainage channels leading from the site into San Francisco Bay. This was based on the observation that the species composition of sediment-dwelling organisms was typical of a community subject to petroleum contamination. In addition, mussel larvae exposed to marsh sediments exhibited a toxic response, though this response could not be linked to site chemicals.
Remedy Selection: Final clean-up actions (Final Remedy) are summarized in the Remedial Action Plan (RAP), approved the Department of Toxic Substances Control on March 15, 1993. EPA concurred with the RAP by signing a Record of Decision on June 21, 1993. The Final Remedy included excavating contaminated sediments from the drainage channels, placing these with contaminated soils from a used oil recycler, and constructing a vegetated soil cap to cover these soils and sediments. In addition, a deed restriction prohibiting residential development at the site was signed and recorded. These remedial activities were completed during 1995. Monitoring of the cap and the groundwater continues. The site was deleted from EPA's National Priority List in September, 1996.
Four Five-Year Reviews, which evaluate whether the site is protective of human health and the environment, have been completed (2000, 2005, 2010 and 2015). The most recent review (2015) concluded that the remedy at the Liquid Gold Site protects human health and the environment, because all immediate threats at the site have been addressed through the removal of contaminated material, stabilization and capping of on-site contaminated soils, access restrictions such as fencing and warning signs, regular maintenance of engineered control structures, and a deed restriction that restricts land uses. However, in order for the remedy to be protective in the long-term, Union Pacific Railroad must update the deed restriction to comply with current California regulations and finish realigning the fence to completely enclose the vegetated cap.
Cleanup Results to Date
Remedial activities at the site were completed in 1995, and the site was de-listed in 1996. Three Five-Year Reviews have been completed (2000, 2005, and 2010), which conclude that the site is currently protective of human health and the environment.
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.
Southern Pacific Transportation Company, now Union Pacific Railroad
Documents and Reports
|10/28/10||5 Year Public Notice|
|10/26/10||Liquid Gold 2010Third Five-Year Review|
|09/21/10||Third Five Year Review|
|09/03/15||Fourth Five-Year Review Report for Liquid Gold Oil Corporation Site, Contra Costa County, California|
Public Meetings: The fourth Five Year Review report was completed in September 2015, and is available in the "Documents and Reports" section of this web page. It is also available at the information repositories listed below. If you have questions about the site or the report, please contact one of the EPA or DTSC contacts listed below.
Public Information Repositories
The public information repositories for the site are at the following locations:
Richmond Public Library
325 Civic Center Plaza
Richmond, CA 94804
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
700 Heinz Avenue, 2nd Floor
Berkeley, CA 94710
After Hours (Emergency Response)