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About Us:  Cleanup

Thermal incineration unit
PCB OU thermal incineration unit, 1996

Each environmental contaminant and circumstance requires a unique approach to cleanup. Many alternatives are considered, researched, tested, and evaluated. Several groups are involved with cleanup negotiations at Crab Orchard National Wildlife Refuge including the FWS, USEPA, Illinois EPA, and parties financially responsible for cleanup, when applicable. Criteria for alternative selection include: overall protection of human health and the environment, effectiveness, efficiency, implementability, and cost. The CERCLA process highly values public input, and public comments are also considered in selection of cleanup alternatives.


Physical cleanup begins as soon as cleanup action plans are completed

PCB OU repository
PCB OU Repository under construction

 and agreed upon. Cleanup of any number of Operable Units (OUs) can be occurring at any one time. The CERCLA cleanup at the Refuge has been divided into seven Operable Units based on types of contamination. These OUs are in different phases of investigation, cleanup, and long term monitoring and include the following:

    Polychlorinated Biphenyls (PCB) OU

   Metals Areas (MA) OU

   Explosives/Munitions Manufacturing Areas (EMMA) OU

EMMA OU site
EMMA OU site of a detonated land mine

   Miscellaneous Areas (MISCA) OU

   Water Tower Areas (WT) OU

   Lake Monitoring (LM) OU

   Additional and Uncharacterized Sites (AUS) OU

Since 1982, several OUs have been designated and closed as cleanup was completed:

  • Five lead-painted water towers in the Water Tower OU were removed, and approximately 2800 cubic yards of lead contaminated soils underneath them excavated and transported offsite for treatment.
  • Cleanup was completed in 1996 at three sites comprising the Metals OU. Nearly 40,000 cubic yards of soil contaminated with heavy metals was excavated, treated, and placed in an engineered landfill on the refuge.

    Digestor lid
    MISCA OU Site 36 digestor lid removal

  • In 1996, Slumberger Industries excavated and incinerated over 117,000 tons of soils contaminated with PCBs, heavy metals, and TCE from a fifty-acre site known as the PCB OU. This soil was placed in an engineered landfill on the refuge.
  • In 1999, the U.S. Army excavated and replaced soils contaminated with explosives and lead as part of the Explosives/Munitions Manufacturing Areas (EMMA) OU. The Army burned 800 pounds of TNT removed from these areas, excavated 20 acres containing unexploded ordinances, and reforested 84 acres disrupted by activities.

As contaminant removal is completed, OUs on Crab Orchard National Wildlife Refuge are officially closed. These closures are approved by the DOI, USEPA, and Illinois EPA. Operable Unit closures mark the successful completion of contaminant cleanup to safe levels for humans, plants, and wildlife, and are the ultimate goal for the FWS.

water tower collage
Water Tower 1, once supplying water to the Crab Orchard National Wildlife Area residents, was felled and removed August 2000


Polychlorinated Biphenyls (PCB)

This OU consists of 4 sites totaling approximately fifty acres within the Crab Orchard National Wildlife Refuge.  The Record of Decision (ROD), August 1990, documented contamination of PCBs, heavy metals (lead and cadmium) and organic compounds (trichloroethylene (TCE)) as a result of past industrial practices.  Schlumberger entered into a settlement agreement to conduct remediation. Schlumberger completed incineration of approximately 65,412 cubic yards of PCB-contaminated soil containing concentrations greater than 25 parts per million (ppm) in June 1997.  Some 102,660 cubic yards of contaminated soils containing less than 25 ppm PCBs along with the incinerator ash were disposed in an on-site 3-acre repository. Incinerator ash containing hazardous levels of lead were stabilized and disposed of in an engineered 2-acre on-site landfill. 

 It was discovered that groundwater at 2 sites is contaminated with solvents including TCE above regulatory standards.  In June, 2000, USEPA issued an Explanation of Significant Differences (ESD) to the PCB OU.  The ESD selected multi‑phase extraction of chlorinated solvent contaminated groundwater, with limited phytoremediation and monitored natural attenuation, as the remedial technology to address the groundwater contamination.  The results of the pilot test conducted as part of design studies indicate that multi‑phase extraction will not be effective in significantly reducing TCE contamination at the site.  USEPA plans to issue an Amendment to the Record of Decision to select a second remedy.

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Metals Areas (MA) OU

This OU consists of 3 sites totaling approximately 25 acres within the Crab Orchard National Wildlife Refuge.  The Record of Decision (ROD), March 1990, documented lead, cadmium, zinc, and cyanide contamination.  Over 40,000 cubic yards of soils were removed and treated as necessary or disposed in an engineered 3-acre on-site landfill in 1995 and 1996.  The USFWS is conducting long term operation and maintenance which consists primarily of groundwater monitoring, leachate disposal, and maintenance of the onsite landfill.

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Explosives/Munitions Manufacturing Areas (EMMA) OU

Fifteen sites were investigated by the Department of Army as lead agency.  Many of the sites appeared to have been used for munition disposal/detonation.  The chemicals of concern included trinitrotoluene (TNT), dinitrotoluene (DNT), High Melting Explosive (HMX), and Research-Developed Explosive (RDX).  In addition to contamination from explosives, elevated levels of metals were identified.  A Record of Decision (ROD), issued February 1997, selected excavation and off-site disposal of contaminated soils and capping at two sites. Approximately 6,110 cubic yards of soil was excavated and disposed, and 800 pounds of TNT nuggets were burned.  Remedial action was completed in September 2001.  The Army is conducting operation and maintenance activities of the cover.

The Army completed removal of unexploded ordnance at five of 15 sites.  The response consisted of excavation of 20 acres of unexploded ordnance and reforestation of 83 acres to eliminate intrusive land use activities.  Institutional controls and land use restrictions are in place.  The Army will conduct periodic reviews to evaluate the effectiveness of the institutional controls.

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Miscellaneous Areas (MISCA) OU

This OU was formed to investigate sites identified by O’Brien and Gere as requiring additional investigation and/or monitoring or maintenance.  Twenty one sites were investigated.  Three sites, Site 14, Site 22A and Site 36, were identified as requiring remediation.  Site 22A, the location of a former wood-treating facility contaminated with pentachlorophenol, was cleaned up in the 1990s under a removal action.   Site 14 is an area of soil and groundwater with primarily solvent contamination adjacent to a former ink manufacturing facility.  A Record of Decision (ROD) issued October 2001 for Site 14, selected a remedy consisting of demolition of a building, excavation and off-site disposal of soils into a permitted landfill, treatment of groundwater water that seeps into the excavation area, and groundwater monitoring. 

A Unilateral Administrative Order was issued by USEPA to Illinois Tool Works directing the remediation of the site.  Remediation is anticipated to begin in Fall, 2005.  Site 36, the former Refuge wastewater treatment plant, had sludge, sediment, and soil contaminated primarily with PCBs and cadmium.  The dilapidated wastewater treatment plant had been in continuous operation since World War II and received wastewater from industrial tenants.  The Record of Decision, issued September 2002, selected a remedy consisting of demolition and disposal of the contaminated wastewater treatment plant, treatment of water from the east pond, excavation and off-site disposal of soils into a permitted landfill, and groundwater monitoring.  The Bureau of Reclamation awarded a contract for remediation to Pangea Group, Inc. and provided construction management support.  FWS demolished the contaminated wastewater treatment plant.  Approximately 39,000 cubic yards of soils, sludges, and building debris were removed and disposed off-site in a permitted landfill.  The remediation was completed in 2006.  Trees were planted to reforest the site.  FWS will conduct long term groundwater monitoring and monitor the effectiveness of reforestation.    

Site 14 is an approximately 2 acre site contaminated primarily with petroleum hydrocarbons (benzene, toluene, ethyl benzene, and xylene).  A Record of Decision issued in October 2001, selected a remedy consisting of demolition of a building, excavation and off-site disposal of soils into a permitted landfill, treatment of groundwater that seeps into the excavation area, and groundwater monitoring.  A Unilateral Administrative Order was issued by USEPA to Diagraph (Illinois Tool Works is the successor to Diagraph) directing the remediation of the site.  Illinois Tool Works completed the excavation and off-site disposal portion of the remedial action in the Summer of 2007.  They excavated to lower cleanup numbers in lieu of completion of a limited human health risk assessment and performance of monitored natural attenuation of groundwater.  Illinois Tool Works will conduct groundwater monitoring to evaluate the performance of the remedy in achieving groundwater cleanup standards.

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Water Tower Areas (WT) OU

A removal action was conducted to remediate lead contaminated soils at three water tower areas on the Refuge and the Refuge Visitor Center in 1991 and 1992.  Approximately 2,800 cubic yards of lead contaminated soils were excavated and disposed off-site.  The contamination was from the lead-based paint that fell onto the soil during past sandblasting operations at those towers.  The 3 water towers were demolished and removed by the USFWS.  This OU is complete.

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 Lake Monitoring (LM) OU

The Lake Monitoring Operable Unit consists of the water and sediment within the boundary of Crab Orchard Lake.  A Preliminary Screening Analysis was conducted in 2000-2001 to assess contaminants in the lake to evaluate risk.  As there is a potential risk to some ecological receptors, the USFWS is conducting further evaluation; however, that investigation will be incorporated into other OUs.

The Illinois Department of Natural Resources (IDNR) publishes advisories of fish consumption.  An advisory against the consumption of certain species of fish at Carb Orchard Lake has been in effect since the early 1980s because of elevated levels of PCBs and recently mercury.  PCB levels in fish have decreased since the original advisory.

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Additional and Uncharacterized Sites (AUS) OU

DOI formed the AUS OU  from 1997 to 1999 to address potential releases of hazardous substances not included in existing OUs at the Refuge.   The AUS OU sites are spread throughout the former Illinois Ordnance Plant area and include former manufacturing facilities, industrial storage areas, and disposal areas.  The Preliminary Assessment/Site Inspection revealed elevated levels of heavy metals and pesticides in soils and concentrations of solvents, including trichloroethylene (TCE), exceeding groundwater regulatory standards.  Thirty-two sites are recommended for remedial investigation. An Administrative Order on Consent (AOC) was entered into with General Dynamics Ordnance & Tactical Systems (GDO&TS) for performance of the RI/FS at the AUS OU with USFWS conducting the baseline risk assessment.  The RI/FS will further define the nature and extent of contamination.

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Crab Orchard National Wildlife Refuge

8588 Rt. 148
Marion, IL 62959

Phone:  (618) 997-5491  

Email:  CrabOrchardCleanup@fws.gov


Last Updated:  August 6, 2007