Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
Omega Chemical Corporation
EPA #: CAD042245001
County: Los Angeles
Congressional District: 34 and 39
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Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 09/29/98
Final Date: 01/19/99
The Omega Chemical Corporation facility was located at 12504 and 12512 East Whittier Boulevard in Whittier, California (former Omega property), and was a refrigerant and solvent recycling, reformulation and treatment facility that operated from approximately 1976 to 1991. Drums and bulk loads of waste solvents and other chemicals from various industrial activities were processed at the facility. As a result of the operations and spills and leaks of various chemicals, the soil and groundwater beneath the former Omega property became contaminated with high concentrations of tetrachloroethylene (PCE), trichloroethylene (TCE), Freons 11 and 113 and other contaminants. Contaminated groundwater extends four and one-half miles downgradient (south/southwest) of the former Omega facility. In January 1999, EPA placed the Omega Chemical Corporation Superfund Site (Omega Site) on its National Priorities List.
EPA manages the Omega Site as three operable units (OUs): OU-1 includes the contaminated soil and groundwater at and in the immediate vicinity of the former Omega property; OU-2 is composed of groundwater contamination outside and generally downgradient (south-southwest) of OU-1; and OU-3 addresses vapor intrusion from the Omega Site that has occurred in several buildings on and in close proximity to the former Omega facility. Vapor intrusion is the process by which contaminant vapors in the soil and/or groundwater migrate through subsurface soils and enter overlying buildings.
Contaminants and Risks
- Soil and Sludges
Subsurface soil and groundwater at the Omega Site contain a variety of volatile organic compounds (VOCs) including PCE, TCE and Freon. As a result of an EPA drum removal action during 1995-96, the primary source of the contamination has been removed from the former Omega Property and that area is fenced off from public access. EPA is taking action to ensure that no one is exposed to unsafe levels of hazardous substances associated with the Omega Site. Without proper action and attention to the contamination associated with this site, people may come into direct contact with contaminated soils or groundwater and may suffer adverse health effects as a result.
Who is Involved
The Omega Site is being addressed through Federal and potentially responsible parties’ actions.
Investigation and Cleanup Activities
Contamination at the Omega Site is being addressed through both non-time critical removal action and remedial action authorities under the Federal Superfund law (the full name of the Superfund law is the Comprehensive Environmental, Response, Compensation, and Liability Act, “CERCLA”).
BACKGROUND AND INITIAL ACTIONS
Prior to 1995, the lead regulatory agency for the former Omega facility was the State of California Department of Toxic Substances Control (DTSC). During the 1980's, several assessments of subsurface conditions were performed, including sampling of soil gas and groundwater. In 1987, a 500-gallon underground storage tank was removed. From 1991 through 1994, DTSC, with EPA's Superfund Division support, actively pursued the owner/operator of the Omega facility to remove the wastes and cleanup the Omega Site. Because the owner/operator failed to address releases and threats of releases of hazardous substances at the Omega Site, DTSC requested that EPA’s Emergency Response Section assess the need for a removal action at the Omega Site. Through this site assessment, EPA determined that a removal action was necessary and issued an Action Memorandum on May 3, 1995. On May 9, 1995, EPA issued a Unilateral Administrative Order (UAO) to approximately 170 major generator potentially responsible parties (PRPs), all of whom sent 10 tons or greater of hazardous materials to the former Omega property, to perform removal activities at the Site. These major contributing parties thereafter formed a workgroup called the Omega Chemical Site Potentially Responsible Parties Organized Group, or “OPOG”. During 1995, EPA oversaw removal activities performed by the PRPs under the 1995 UAO that included the removal and off-site treatment of approximately 3,000 drums of hazardous waste, 60 cubic yards of hardened resin material, hundreds of empty contaminated drums, numerous cylinders and various other smaller containers. The UAO also required emptying two rainwater sumps and four evaporators, cleaning two cooling towers, removal of 67 refrigerant gas cylinders, decontamination of remaining equipment and structures, and disposal of 40,000 gallons of rinsate and decontamination water.
In 1996, OPOG, with EPA oversight, undertook the collection and analyses of some preliminary subsurface soil and groundwater samples at the former Omega property and surrounding locations. Investigation work in 1996 consisted of conducting a shallow soil gas survey at the former Omega property that included 31 samples collected at three different depths. This soil gas survey allowed for further analysis of the Omega Site's geology and hydrogeology, and the identification of any materials considered "grossly contaminated." The only grossly contaminated material identified was near-surface soil contained within the loading dock sump; that material was excavated and removed from the former Omega property. A preliminary groundwater investigation conducted in 1996 concluded that elevated levels of volatile organic compounds were present in groundwater downgradient of the former Omega property.
To better manage large site cleanups, EPA addresses a Site by designating Operable Units (OUs) which represent discrete elements of the overall site cleanup. The Omega Site has three OUs: OU-1 addresses the contaminated soil and groundwater in the immediate vicinity of the former Omega Chemical facility; OU-2 addresses the contaminated ground-water downgradient of OU-1 that has been impacted by contamination from the Omega facility; and OU-3 addresses vapor intrusion from the Omega Site that has occurred in several buildings on and in close proximity to the former Omega facility.
Groundwater within the OU-2 area is used as a source of drinking water by several municipal and private water purveyors. Most of the drinking water wells located in the OU-2 area draw water primarily from deeper portions of the aquifer from depths at or greater than 200 feet below ground surface (bgs) and are not currently impacted by groundwater contamination. However, a few drinking water wells in the area draw water at about the 200 feet bgs level and have had some contaminants detected. These wells are currently equipped with wellhead treatment units which are comprised of granular activated carbon (GAC) filters. The GAC filter removes the contaminants from the water to ensure that it meets drinking water standards. Drinking water for the Cities of Whittier, Santa Fe and Norwalk is tested regularly prior to distribution to the public, and all tap water meets State and Federal drinking water standards.
OPERABLE UNIT 1: SOIL AND GROUNDWATER AT OR NEAR THE FORMER OMEGA PROPERTY INVESTIGATION
On April 1, 1999, EPA issued Special Notice Letters to the PRP group and commenced negotiations for the performance of additional work at the Omega Site. On February 28, 2001, a Partial Consent Decree was entered by the United States District Court memorializing the terms of this agreement. Under this agreement, the Settling Defendants agreed to pay a portion of past costs and perform the following work at the Omega Site:
1) Implementation of a Remedial Investigation / Feasibility Study (“RI/FS”) for contamination in the vadose zone (i.e., the soil) within the “Phase 1A area” of the Omega Site. The “Phase 1A” area includes soil and groundwater contamination on and near the former Omega property. The Phase 1A area is also known as OU-1;
2) Performance of an Engineering Evaluation and Cost Analysis (“EE/CA”) addressing groundwater contamination in the Phase 1A area;
3) Implementation of the response action selected in EPA’s Action Memorandum at the conclusion of the EE/CA;
4) Performance of a risk assessment within the Phase 1A area; and
5) Installation of up to three groundwater monitoring wells at locations downgradient of the Phase 1A area and upgradient of the City of Santa Fe Springs water supply well.
In early 1999, OPOG undertook additional field investigation activities with EPA oversight. Field activities included the installation of three groundwater monitoring wells immediately downgradient of the former Omega property; collection of soil and soil gas samples from each well boring, and the collection of groundwater samples for laboratory analysis. Aquifer tests were also performed on the newly-installed wells. In August 2001 and March 2002, OPOG installed another three monitoring wells, including one well located on the upgradient (northeast) side of the former Omega property. Work under the Partial Consent Decree is conducted under EPA oversight.
OPOG completed a work plan to implement the OU-1 vadose zone RI/FS, which was approved by EPA in September 2003. Additional work plan addenda were also submitted to EPA to support supplemental data collection. Data collection for the OU-1 RI was completed in 2006 and the RI report was completed in November 2007. The OU-1 FS report was completed in May 2008.
OPERABLE UNIT-2: GROUNDWATER INVESTIGATION
In August 2010, EPA completed an OU-2 RI/FS, which evaluates the nature and extent of OU-2 groundwater contamination, assesses the potential risks posed by this contamination to human health and the environment, and develops and evaluates alternative remedial actions to address the contaminated groundwater.
OPERABLE UNIT 3: INDOOR AIR AT OR NEAR THE FORMER OMEGA PROPERTY INVESTIGATION
In 2004, indoor air samples from buildings on and near the former Omega property were evaluated for vapor intrusion from contaminated soil and groundwater. In April 2006, EPA issued an Action Memorandum to address indoor air contamination at the Skateland property by implementing a sub-slab depressurization (SSD) system. OPOG organized and funded the purchase of the Skateland property in September 2006 and implemented an EPA-approved response action that permanently discontinued its use as a commercial building.
After further studies. it was found that vapor intrusion was occurring in other buildings within or near OU-1. EPA entered into an agreement with OPOG in 2009 to address indoor air contamination at other buildings. Under the agreement, OPOG has taken a number of actions and has installed two interim Soil Vapor Extraction Systems (SVE), to address vapor intrusion at buildings in and near the OU-1 area. These actions will be consistent with (and in some respects are an early start on) the long-term cleanup of the OU-1 soils. As of 2012, nearly 7,000 pounds of contaminants have been removed with the two Interim SVE systems. The 2009 agreement requires OPOG to continue periodic indoor air monitoring in several buildings near the former Omega facility. EPA oversees OPOG’s OU-3 work. Once OU-1 remedy is constructed and operating, the interim cleanup systems for OU-3 will no longer be needed.
OPERABLE UNIT-1: SOIL AND GROUNDWATER AT OR NEAR THE FORMER OMEGA PROPERTY RECORD OF DECISION
In 2005, OPOG with EPA oversight completed a Environmental Evaluation/Cost Analysis (EE/CA), which evaluated potential response actions for groundwater contamination within the OU-1. Cleanup alternatives evaluated in the EE/CA are summarized in EPA's Proposed Plan dated August 2005. EPA issued an Action Memorandum in September 2005, which authorized construction and operation of a groundwater pump and treatment system based on the results of the EE/CA. Construction of the pump and treatment system was completed in 2009, after which the system began operating.
In September 2008, EPA issued a Record of Decision (ROD) selecting a soil cleanup remedy for OU-1. The remedial action selected in the ROD consists of a soil vapor extraction (SVE) system to remove and treat the chemical vapors in the soil within OU-1. A series of SVE wells will be used to pull the contaminant vapors out of the soil and into a granular activated carbon (GAC) filter. Once the contaminants are removed by the GAC filter, the clean air created through this process will be released into the atmosphere.
OPERABLE UNIT-2: GROUNDWATER RECORD OF DECISION
In August 2010, EPA completed an OU-2 RI/FS, which evaluates the nature and extent of OU-2 groundwater contamination, assesses the potential risks posed by this contamination to human health and the environment, and develops and evaluates alternative remedial actions to address the contaminated groundwater. EPA issued a Proposed Plan for OU-2 that identified its preferred interim groundwater containment remedy. An interim remedy can be put in place in a more timely manner than a full final cleanup remedy. EPA held public meetings and received public comment from August 23rd through November 22, 2010 which includes two extensions.
After considering public comments, EPA selected an interim remedy to capture, contain, and treat contaminated groundwater. The selected interim remedial action is presented in the Record of Decision (ROD) dated September 20, 2011 and can be found in the "Documents and Report Section" below. The overall objective of the interim remedy is to protect human health and the environment by preventing further spreading of the contaminated groundwater. Once the contaminated groundwater has been extracted and treated, it is expected to be used for drinking water and will meet state and federal drinking water standards. A ROD fact sheet summarizing the decision can be found in the Fact Sheet Section below.
OPERABLE UNIT 1: SOIL AND GROUNDWATER AT OR NEAR THE FORMER OMEGA PROPERTY REMEDIAL DESIGN
The final long term SVE system to fully clean up the soils will be designed by the end of 2012. Once the soils have been cleaned up in OU-1 and the source of the vapors are eliminated, the interim SVE and SSD systems for OU-3 should no longer be needed.
Cleanup Results to Date
With the removal of the over 2,700 drums and the grossly contaminated soils from the Omega Property, EPA removed an imminent threat to the environment and health of the public. Construction of a pump and treatment system to contain the high concentration groundwater contamination within the OU-1 was completed and began operating in 2009. The treated water is discharged to a nearby sanitary sewer. Two interim Soil Vapor Extraction (SVE) systems, were installed to address vapor intrusion at buildings in and near the OU-1 area. The first and second interim SVE systems were installed in June 2010 and March 2012, respectively. These systems have effectively reduced the concentrations of contaminants in the indoor air of the affected buildings.
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.
Documents and Reports
Public Information Repositories
The public information repositories for the site are at the following locations:
Whittier Public Library
7344 S. Washington Avenue
Whittier, CA 90602
Ask for the Omega Site information at the
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
9211 Oakdale Avenue
Chatsworth, CA 91311-6505
San Diego, CA 92106
After Hours (Emergency Response)