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Hazardous Waste Cleanup: Dow Chemical (Formerly: Rohm and Haas Chemicals LLC) in Bristol, Pennsylvania

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Cleanup Status

EPA sets national goals to measure progress toward meeting the nation’s major environmental goals.  For Corrective Action, EPA evaluates two key environmental indicators for each facility: (1) current human exposures under control and (2) migration of contaminated groundwater under control.  In September 2005, EPA determined that human exposure was under control.  In August 2019, EPA determined the migration of contaminated groundwater was under control.

The Facility was investigated and remediated under both the EPA RCRA Corrective Action program and the PADEP Act 2 program.  Due to the Facility’s large size and diversity of operations, it was divided into study areas for the purpose of investigation and remediation.  Remediation is complete at several areas of the site.  Other areas are completing the investigation/remediation work.

Bristol Landfill - Remediation is complete. The waste material is incased in a hydraulic barrier (slurry wall) and a RCRA-type cap.  Construction of the containment system was completed in 1996.  Post-remediation monitoring of the groundwater and cap continue. 

Ammonium Sulfate Area – An ammonium sulfate groundwater plume is being monitored under a Protectiveness Assessment Plan to evaluate the potential migration of the plume to the Delaware River.  If monitoring shows that groundwater migration may contaminate the Delaware River above Surface water Quality Standards, groundwater remediation will be required.  The ammoniun sulfate contamination poses an exposure hazard to aquatic life, but not to human health.

Former Wastewater Treatment Area – Remediation is complete except for the assessment of the Former Burning Area remediation. The treatment tanks were removed in 1991.  The treatment basins were filled and covered with clean soil and vegetation in 2013.  The treated water basins (polishing ponds) remain, but environmental investigations show that no additional remediation is needed.  The Burning Area was remediation in 2017, by in-situ chemical oxidation of the deep soil zone, to treat contamination that may migrate to the Delaware River.   Post-treatment monitoring of the Burning Area continues to evaluate the effectiveness of the treatment.

North Parcel – Remediation is complete.  An area of insecticide contamination, the former Bucks County Mosquito Control Commission area, was excavated and backfilled with clean soil in 2011.

Manufacturing Area – Remediation is complete, except for two localized areas: a former ash pile and an area surrounding Well-93.  The former hazardous waste storage tanks and industrial boilers were clean closed in 2004 and 2005, respectively.  A release of methyl methacrylate was remediated in 2010 by excavation and disposal of the contaminated soil.  A release of butyl acrylate and ethyl acrylate was remediated in 2012-2013 by in-situ chemical oxidation of the contaminated soil.  The two remaining areas of contamination will be remediated in 2020 by excavation and disposal of the contaminated soil.

Trailer Staging Area – Investigations are on-going.

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Site Description

Interactive map of Dow Chemical (Formerly: Rohm & Haas Chemicals LLC), Bristol, PA

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The Facility has been an active chemical manufacturing plant since 1917.  It covers approximately 800 acres along the west bank of the Delaware River, in Bristol Township, Bucks County, PA.  The Facility is adjacent to the communities of Croydon and Bristol Borough.

Due to the Facility’s large size and the diversity of operations, it was divided into the following study areas for the purpose of environmental investigations.

Bristol Landfill - The landfill is a 60-acre, pre-RCRA landfill that operated between 1952 and 1975.  It was the primary disposal site for plant waste generated during that period of operation.  The waste material is incased in a hydraulic barrier (slurry wall) and a RCRA-type cap. 

Ammonium Sulfate Area – A dense plume from past land disposal activities in the 1950’s and 1960’s has migrated down through the soil and groundwater to stabilize along the surface of the bedrock.  Monitoring continues to evaluate the stability of the ammonium sulfate plume to ensure that contamination does not migrate to the Delaware River at concentrations that would exceed the Surface Water Quality Standards.

Former Wastewater Treatment Area - The area includes the property that was formerly used for treatment of industrial wastewater in tanks and earthen basins (from the 1950’s until 1991), and landfarming of sludge from the treatment plant (in the 1960’s and early 1970’s).  It covers approximately 140 acres and is zoned for heavy industrial use.  It is bounded by the Delaware River to the south, Hog Run Creek to the west, River Road to the north, and Rohm & Haas Manufacturing Area to the east (across Route 413).  Treatment in the units was discontinued in 1991 when a new, completely tank-based, treatment plant came on-line.

North Parcel – The 110-acre parcel is mostly wooded and wetland, undeveloped land located north of River Road.  It was never used by Rohm and Haas for manufacturing or any other industrial purpose.  However, a small section of the western area, approximately ¼ acre, was used by the former Bucks County Mosquito Control Commission (BCMCC) from the 1950s to early 1970s.  Another section of the western area is used by PADEP to site remediation facilities for the Croydon TCE Superfund Site, under an easement granted by Rohm and Haas. The western area is currently owned by the Heritage Conservancy.  The central and eastern areas are currently owned by Bristol Township. 

Manufacturing Area – The area includes approximately 60 acres involved in the production of a variety of chemicals and intermediates over the years; including plastics, resins, emulsion polymers, and pesticides.  This area is bounded by Otter Creek to the north, Schmidt’s Lake and Lake Idaline to the south, Bristol Borough wastewater treatment plant and Trailer Staging Area to the east, and the Wastewater Treatment Area to the west (across Route 413).  The remaining remediation at two areas will be completed under the PA Act 2 program.

Trailer Staging Area – This 7-acre parcel was backfilled with construction debris, waste material, and dredge spoils in the 1940’s and 1950’s.  There are no records on the specific type or amount of the buried material.  The area is bounded by Otter Creek on the north and east, by the Manufacturing Area on the west, and by the Bristol Borough wastewater treatment plant on the south.  Investigation of this area is being completed under the PA Act 2 program.

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Contaminants at this Facility

The soil and groundwater are contaminated with a variety of organic and inorganic chemicals, frequently localized in area.  No contamination poses an exposure concern under existing and proposed future use.

Details of the contamination are provided in the Documents section:

  • Environmental Indicators Human Exposure Rohm and Haas Company,
  • Environmental Indicator Groundwater for Dow Chemical, and 
  • Statement of Basis for the particular study area.

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Institutional and Engineering Controls at this Facility

Bristol Landfill is controlled by the containment structure and a deed restriction controlling both land and groundwater uses.

Environmental Covenants are in place for the Former Wastewater Treatment Area and the North Parcel.  The Former Wastewater Treatment Area covenant controls land and groundwater use in the open space area     The North Parcel/Croydon Woods area covenant restricts the uses to open space/passive recreation and prevents groundwater use.

Environmental Covenants are proposed for the Ammonium Sulfate Area and the Manufacturing Area to restrict land and groundwater uses.

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Land Reuse Information at this Facility

The property is in continued use for business and manufacturing. The North Parcel and part of the Former Wastewater Treatment Area are open space/passive recreational areas.

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Site Responsibility at this Facility

 The Facility is in Pennsylvania's One Cleanup Program, with investigations and remediations coordinated by EPA and PADEP.

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