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Pacific Southwest, Region 9: Superfund

Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations

Omega Chemical Corporation

EPA #: CAD042245001

State: California(CA)

County: Los Angeles

City: Whittier

Congressional District: 34 and 39

Other Names:

Bulletin Board

On March 31, 2017, a Federal Court approved an agreement between EPA and 66 PRPs to spend an estimated $70 million to implement the majority of EPA’s 2011 OU2 Record of Decision. Pre-design work required by the agreement will begin immediately and continue into 2018.


Description and History

NPL Listing History

NPL Status: Final

Proposed Date: 09/29/98

Final Date: 01/19/99

Deleted Date:


The Omega Chemical Corporation facility, located at 12504 and 12512 East Whittier Boulevard in Whittier, California (the "former Omega property"), 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 were processed at the facility. As a result of spills, leaks, and other chemical releases, 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 more than four 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 soil and/or groundwater migrate through subsurface soils and enter overlying buildings.

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Contaminants and Risks

Contaminated Media
  • Groundwater
  • Air
  • 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 in 1995 and 1996, the primary source of the contamination has been removed and 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.

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Who is Involved

The Omega Site is being addressed through Federal and potentially responsible parties’ actions.

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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.”

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 and operator of the Omega facility to remove the wastes and begin cleanup of the Site. In May 1995, EPA determined that a removal action was necessary and issued an Action Memorandum. 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 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. 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.

Groundwater in 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 at the Site. However, several drinking water wells that draw water from shallower potions of the aquifer. These wells have been shut down or equipped with wellhead treatment units to remove the contaminants. Drinking water for the Cities of Whittier, Santa Fe Springs, and Norwalk is tested regularly prior to distribution to the public to ensure that all tap water meets State and Federal drinking water standards.

Site Studies


On April 1, 1999, EPA issued Special Notice Letters to the PRP group and commenced negotiations for the performance of additional work at the 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) on and near the former Omega property (also known as the Phase 1A area);

2) Performance of an Engineering Evaluation and Cost Analysis (“EE/CA”) addressing groundwater contamination in the Phase 1A area and implementation of the response action selected in EPA’s Action Memorandum at the conclusion of the EE/CA;

3) 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 installed and sampled the three groundwater monitoring wells. Soil and soil gas samples were also collected from each well boring, and aquifer tests were 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 an RI report was completed in November 2007. The OU-1 FS report was completed in May 2008.


In August 2010, EPA completed an OU-2 RI/FS, which evaluated the nature and extent of OU-2 groundwater contamination, assessed the potential risks posed by this contamination to human health and the environment, and developed and evaluated alternative remedial actions to address the contaminated groundwater.


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 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 the OU-1 remedy is constructed and operating, the interim cleanup systems for OU-3 will no longer be needed.

Remedy Selected


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.


In 2010, EPA issued a Proposed Plan for OU-2 that identified its preferred groundwater containment remedy. EPA held public meetings and received public comment on its plan from August through November 2010.

After considering public comments, EPA selected a remedy designed to prevent further spreading of the contaminated groundwater and remove contaminants from the groundwater. The selected 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 remedy requires the construction and operation of one or more groundwater extraction wells to pump contaminated groundwater to the surface, water treatment facilities to remove the contaminants, and pipelines to deliver the treated groundwater to one or more drinking water purveyors or for reinjection back into the groundwater basin. It also requires the construction of new groundwater monitoring wells and monitoring of new and existing wells.

The 2011 ROD was updated in June 2016 with a document known as an "Explanation of Significant Differences," available in the "Documents and Reports" in Record of Decision section below. The ESD expands the possible end-uses of the treated groundwater, removes the preference for a drinking water end-use included in the 2011 ROD, adds the California Maximum Contaminant Level (MCL) for hexavalent chromium as a potential treatment requirement, and updates EPA's cleanup cost estimates.

Remedy Design


The second SVE system to fully clean up the soils was turned on during 2015. Although the system is operating, the system has not been declared operational and functional yet because the system is not operating at the correct extraction rates yet. In addition the system is not meeting the noise reduction parameters outlined in the design reports. EPA is working with the Responsible Parties so that the system will eventually meet the design operational parameters which will allow the Agency to conduct the Operational and Functional Inspection at the site.


In March 31, 2017, a Federal court approved an agreement between EPA and 66 “Potentially Responsible Parties” (PRPs) to spend an estimated $70 million to implement the majority of EPA’s 2011 Record of Decision for OU2. A copy of the agreement and the Court Order approving the agreement are available in the Legal Documents section below.

The PRPs agreed to begin preparation of initial planning documents for design of the remedy upon lodging of the agreement. Pre-design and design work on the new water treatment systems, groundwater extraction wells and piping is now underway and expected to continue into 2018, with construction of the remedy expected to begin in 2019. EPA will oversee design and construction of the remedy, which will remediate contaminated groundwater in an area extending from OU1 to about Telegraph Road in Santa Fe Springs, a distance of approximately three miles. The PRPs also agreed to install and sample three groundwater monitoring well clusters to provide data that EPA will use to determine what additional investigation and/or remediation is needed to address contaminated groundwater downgradient of Telegraph Road. Installation of the well clusters is expected in to begin in summer 2017 The approved Pre-Design Investigation and Leading Edge Investigation Work Plans are available in the Technical Documents section below.

To provide up to date data for remedial design, EPA has been analyzing groundwater samples from existing groundwater wells semi-annually or annually. Results for the years 2008-2014 are available in groundwater monitoring reports available in the Documents and Reports section below. The PRPs collected and analyzed samples in December 2015 and will continue sampling annually, with the most recent sampling event completed in October 2016. Results for 2015 are also available below. The approved Work Area Monitoring Plan, which describes the planned sampling, is available in the Technical Documents section below.

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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.

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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.

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Documents and Reports

Hide details for Administrative RecordsAdministrative Records
08/26/10Interim Remedy OU-2 Administrative Record (8-26-10)
09/30/11Remedial, Operable Unit 02, Interim Remedy, Update 1
2005/2006 Oversight Costs Dispute, Supplement #1
Access Order AR, Remedial
Indoor Air Removal
Non-Time-Critical Removal Action
Non-Time-Critical Removal Supplement 1 & 2
Operable Unit #1
OU 01, Update #1
Oversight Costs Dispute Suppl #1
Remedial, Operable Unit 02 Interim Remedy, Suppl #2
Hide details for Community InvolvementCommunity Involvement
07/23/01Community Involvement Plan
Hide details for Fact SheetsFact Sheets
12/01/00Public Input Requested
07/01/01Consent Decree Signed--Work Begins at Omega Chemical Superfund Site (in English y en Espaņol)
04/01/02Progress at the Omega Chemical Superfund Site (in English y en Espaņol)
09/01/03Omega Chemical Superfund Site Update
11/01/04EPA Evaluates Indoor Air at Omega Chemical Site
08/01/05Proposed Plan for Interim Groundwater Action
01/01/07Omega Chemical Superfund Site Update
02/29/08Update on Site Activities
06/02/08Proposed Plan for Soil Cleanup
02/20/09EPA Selects Cleanup Plan for Soils at Omega Site
09/15/09EPA Issues Draft Remedial Investigation Report for Downgradient Plume at Omega Site
08/11/10Omega OU-2 Proposed Plan for the Groundwater Contamination, Comment Period from August 23-Sept. 21, 2010
08/30/10EPA Extends Public Comment Period on Proposal for Groundwater Cleanup at Omega Chemical Corporation Superfund Site, Operable Unit 2 August 23 - September 21, 2010
10/19/10EPA Extends Public Comment Period on Proposal for Groundwater Cleanup at Omega Chemical Corporation Superfund Site to November 22, 2010
11/17/11U.S. EPA "What You Should Know About Vapor Intrusion"
11/30/11EPA Selects Remedy for Groundwater Contamination at Operable Unit 2
03/14/13Tetrachloroethene (also known as perchloroethylene, PERC or tetrachloroethene) Information Fact Sheet
03/14/13Vapor Intrusion: Answers to Frequently Asked Health Questions Fact Sheet
03/21/13Public Outreach to Select Homeowners in Whittier, CA
Hide details for Legal DocumentsLegal Documents
02/28/01Partial Consent Decree
09/01/05De Minimis Settlement, Administrative Order on Consent, U.S. EPA Docket No. 2004-13
11/06/06Settlement Agreement
11/09/09Administrative Settlement Agreement and Order on Consent for Removal Action - Indoor Air
10/06/10Remedial Design Remedial Action Consent Decree OU-1 (without signatures)
03/31/17OU2 Consent Decree and Court Order
Hide details for Records of DecisionRecords of Decision
09/27/05September 2005 Action Memo for OU-1 Groundwater
04/06/06April 2006 Action Memo for Indoor Air
09/01/08Record of Decision - Operable Unit 1( Soils) Omega Chemical Corporation Superfund Site Whittier, California
09/20/11Interim Action Record of Decision - Omega Chemical Corporation Superfund Site Operable Unit 2, Los Angeles County, California, 9/20/11
06/10/16Explanation of Significant Differences, OU2 and Declaration Page (508 Compliance)
Hide details for Technical DocumentsTechnical Documents
06/01/03Phase 2 Groundwater Characterization Study
04/06/04Conceptual Cost Estimate for Sitewide Remedial Action
11/09/07Final Human Health Risk Assessment For On-Site Soils
11/14/07Final On-Site Soils Remedial Investigation Report - OU-1
05/21/08Final Feasibility Study for Onsite Soils OU1
06/04/09Draft Omega RI Report
08/01/10Final Feasibility Study Report for Omega Chemical OU2, August 2010
08/01/10Final Remedial Investigation for Omega Chemical Operable Unit 2, August 2010 (Section 1 through Section 9)
08/01/10Final Remedial Investigation for Omega Chemical Operable Unit 2, August 2010 (Appendices)
08/01/10Final Remedial Investigation for Omega Chemical Operable Unit 2, August 2010 .(Appendices A to N, excluding F)
05/01/12Groundwater Monitoring Report for 2008 and 2009
06/01/12Groundwater Monitoring Report for 2010 and 2011
08/01/12MW32 Well Installation and Sampling Report
08/01/15Groundwater Monitoring Report for 2012 - 2014
03/18/162015 Groundwater Monitoring Report (OU2)
11/18/16Approved OU2 Work Area Monitoring Work Plan
04/06/17Approved OU2 Pre-Design Investigation Work Plan
04/12/17Approved OU2 Work Plans: Leading Edge Investigation, Remedial Design
07/21/172016 Groundwater Monitoring Report (OU2)

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Community Involvement

Public Meetings: A public meeting was held on August 18, 2016 at the Presbyterian Intercommunity Hospital (Auditorium) in Whittier, CA on a proposed settlement to build and operate groundwater cleanup facilities for OU2 of the Omega Chemical Corporation Superfund Site. The procedings were recorded by a court reporter.

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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
(562) 567-9900
Ask for the Omega Site information at the
Reference Desk

The most complete collection of documents is the official EPA site file, maintained at the following location:

Superfund Records Center

Mail Stop SFD-7C

95 Hawthorne Street, Room 403

San Francisco, CA 94105

(415) 820-4700

Enter main lobby of 75 Hawthorne street, go to 4th floor of South Wing Annex.

Additional Links

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EPA Site Manager
Wayne Praskins
Rosemarie Caraway
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Jackie Lane
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
State Contact
Don Indermill, CA DTSC
Chatsworth Field Office
9211 Oakdale Avenue
Chatsworth, CA 91311-6505
PRP Contact
Ed Modiano, De Maximis, Inc.
1322 Scott Street, Suite 104
San Diego, CA 92106
Community Contact
Other Contacts
After Hours (Emergency Response)
(800) 424-8802

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