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Hazardous Waste Cleanup: Delaware City Refinery (Motiva) in Delaware City, Delaware

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The Refinery entered into the EPA Corrective Action program through a permit in November 1988. In September 2003, Department of Natural Resources and Environmental Control (DNREC) issued a Corrective Action Permit to Motiva and DNREC is the lead agency for Corrective Action for this facility.

Cleanup Status

Thirty-five Solid Waste Management Units (SWMUs) were identified and investigated and areas of groundwater contamination were delineated. Contaminates found through the various studies include metals, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), and chlorinated solvents. Environmental work conducted at the Site is summarized in the following Reports, submitted to EPA and DNREC:

  • Background Information Survey Report (Dames & Moore, 1991a)
  • Identification of the Potential for an Occurring or Past Release Study Report (Dames & Moore,1991b)
  • Verification of Release Study (VRS) Report (Dames & Moore, 1995)
  • Phase I Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) Report (URS, 2005)
  • Baseline Ecological Risk Assessment (URS, 2005)
  • Interim Measures Report, Solid Waste Management Units 20B and Portions of 24B (URS, 2006)
  • Interim Report – Southern Extent of Dissolved Phase Plume (URS, 2007)
  • Interim Report – Dissolved Phase Plume Delineation – Phase II (URS, 2008)
  • Baseline Ecological Risk Assessment (URS, 2010)
  • Human Health Risk Assessment (URS, 2010)
  • Phase II RCRA Facility Investigation SWMU Report (URS, 2010)
  • Phase II RCRA Groundwater Report (URS, 2010)
  • Guard Basin 4 Interim Measures Report (URS, 2013)
  • Oily Sediment Area Interim Measures Report (URS, 2013)

Currently, three SWMUs are under post-closure care, two SWMUs are near closure (Industrial Waste Landfill and Fly ash Ponds) and two others, Guard Basin Four (GB4) and the Oily Sludge Area (OSA) are being remediated through interim measures.

During the Phase I RFI investigation, floating free-phase hydrocarbon was found in groundwater in five areas. In 1994, prior to the RFI, Motiva installed free-phase hydrocarbon recovery systems. Currently, four areas of the facility have free-phase hydrocarbon recovery systems, and with product removal, four of the original eleven systems have been removed.

The groundwater investigations delineated the areas where groundwater is impacted from releases from the refinery. The investigations show that contaminants have not migrated beyond site property boundaries or into surface waters above levels of concern to human health or the environment. Site-wide groundwater monitoring is also performed at approximately 140 monitoring wells to identify potential changes to the location and characteristics of the area of impacted groundwater.

A groundwater remediation pilot project was initiated in two areas at the Facility, but was discontinued in February 2011, after results showed limited effectiveness. Other groundwater clean-up options will be considered in the Corrective Measures Study, to be submitted to DNREC in the near future.

The Environmental Indicator Forms discuss that current human exposure to site contaminants is under control, and that further evaluation of groundwater is nearing completion to determine whether migration of contaminated groundwater is under control.

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Site Description

Interactive Map of Delaware City Refinery, Delaware City, Delaware


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The Refinery is located on 5,050-acres approximately one-mile northwest of Delaware City, Delaware. The refining operations occupy about 1,000-acres. The facility commenced operation in 1956. The facility processed a variety of crude oils and currently produces about 180,000 barrels of petroleum product a day. Production has included diesel, gasoline, jet, fuel oil, aromatics, and methanol and propane fuels. The areas north and west of the refinery are industrial, and include some RCRA and Superfund sites, and the area south of the refinery is open fields or farmland. The Delaware River lies to the east of the facility.

The refinery has had many owners since going on-line in 1956. On May 1, 2004, ownership of the Motiva Refinery passed to Premcor, Inc., and on September 1, 2005 Valero Energy Corporation acquired Premcor, Inc. In November 2009, Valero discontinued production at the refinery and idled the facility. PBF Energy completed the purchase of the refinery from Valero Energy Corporation on June 1, 2010 and restarted the refinery in 2011. Motiva retains the environmental liability for the permitted waste units and historic contamination.

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Contaminants at this Facility

The main site-related contaminants of benzene, toluene, ethyl benzene, xylene (BTEX), and other petroleum hydrocarbons compounds —including Methyl Tertiary Butyl Ether (MTBE) and naphthalene — and some metals. were found in soil, groundwater and sediments. Chlorinated hydrocarbons were also found in groundwater on-site.

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Institutional and Engineering Controls at this Facility

No institutional controls are currently in place. Institutional controls may be incorporated in the Final Remedy Decision.

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    Land Reuse Information at this Facility

    The facility is under continued use.

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    Site Responsibility at this Facility

    RCRA Corrective Action activities  are being conducted under the direction of the Delaware DNREC with assistance from EPA Region 3.

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