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Occidental Chemical Corp

EPA Region 3 (Mid-Atlantic)

Montgomery County
Lower Pottsgrove Township

EPA ID# PAD980229298

15th Congressional District

Last Update: February 2014

Other Names


Current Site Status

The U.S. Environmental Protection Agency is overseeing the cleanup of the Occidental Chemical (Occidental) site. Occidental is responsible for the work and carrying out the cleanup under EPA's oversight. Operable Unit 1, Site Groundwater: Occidental completed the installation of a groundwater extraction and treatment system, necessary for the remediation of the Site groundwater, in January 1999.
Operable Unit 2, Lagoon Soils and Sludges: Two pilot tests for the cleanup of the earthen lagoon material were tried, but both failed because of implementability issues. The information collected as part of the pilot testing confirmation sampling was used to conduct a risk evaluation. Based on the information gathered during the risk evaluation, EPA made a determination that a Focused Feasibility Study (FFS) was required to re-evaluate the remedial action previously selected for the earthen lagoons. On September 29, 2005, EPA and Occidental entered into an Administrative Settlement Agreement and Order on Consent to conduct the FFS. Occidental completed the FFS. In April 2008, an Explanation of Significant Difference (ESD) was prepared to change the remedy for the earthen lagoon sludges to: off-site disposal. The excavation and transportation of the contaminated lagoon sludges and soils began in June 2008 and was completed in September 2008. The sludges were transported to a permanent, licensed landfill facility in Canada. Confirmation samples were collected at the base of the (four) lagoon excavations and the results revealed that the site was cleaned up to the levels required under the April 2008 ESD. Occidental is currently extracting and treating contaminated groundwater at the site. An Explanation of Significant Differences that changed the groundwater performance standard, added two contaminants to the groundwater contaminant of concern list, and described the site institutional controls, was issued in 2013. The first 5-year review for the site was signed in August 2013.

Site Description

Four consecutive owners disposed of industrial wastes at the approximately 250-acre Occidental Chemical Corporation. Prior to the second World War, this site was owned by Jacobs Aircraft Engine Company, which built engines there. The Defense Plant Corporation (DPC) bought the site from Jacobs in 1942, however Jacobs continued to operate and manufacture aircraft engines for DPC until late 1944. In 1945, DPC leased the site to Firestone Tire and Rubber (FTR), which later purchased the site in 1950. FTR made tires and polyvinyl chloride (PVC) resins at the site. In 1980, FTR sold the property to Occidental Chemical Corporation. Occidental continued to manufacture PVC resins at the site until 2005.

From 1942 to 1985, operators disposed of wastes, including cutting oils, metal filings, tires, and PVC sludge resins, into a seventeen-acre solid waste landfill. In 1977, FTR requested permission from the Pennsylvania Department of Environmental Protection (PADEP) to expand this landfill. PADEP granted the expansion and required continuous pumping of groundwater beneath the site to prevent contaminants from moving off-site. In 1985, with state approval, the owner closed this landfill, capping it with a rubber cover and two feet of soil. During the EPA's investigation, the nature and extent of groundwater contamination was further defined. Groundwater pumping continues today.

Another landfill operated on-site; its seven acres were used for disposing residual wastes. In July 1997, PADEP approved a Closure Plan for this landfill, which was then capped in 1998.

A pair of lined lagoons built in 1974 – were closed in 1995 under PADEP's oversight. When they were open, these lined lagoons received the PVC sludge overflow from the plant wastewater treatment system. The site also contained four inactive, unlined lagoons. These unlined lagoons were used to dispose of PVC sludge before the lined lagoons were built. The material from these unlined lagoons was removed by Occidental in 2008 under the Superfund program.

The site surroundings are both agricultural and urban. Pottstown, PA is the closest major town. Approximately 31,000 people live within a two-mile radius of the site. A portion of the site is in the flood plain of the Schuylkill River, which is used both for water supply and for recreational activities.

Site Responsibility
Cleanup of this site is the responsibility of the federal government and the parties potentially responsible for the site contamination.
NPL Listing History
Our country's most serious uncontrolled or abandoned hazardous waste sites can be cleaned using federal money. To be eligible for federal cleanup money, a site must be put on the National Priorities List . This site was proposed to the National Priorities List on June 24, 1988 and formally added to the list on October 4, 1989.

Threats and Contaminants

The groundwater is contaminated with volatile organic compounds (VOCs), including styrene, trichloroethylene (TCE), and vinyl chloride, that are associated with the former manufacturing activities. Extracted groundwater is pumped continuously through a groundwater treatment system that utilizes air stripping technology and carbon as the primary treatment components. Because of this, there is no movement of the contaminated groundwater from the site. The local drinking water supply is provided by a Pottstown municipal facility which depends on water from the Schuylkill River. The former earthen lagoons sludges held PVC material, and were primarily contaminated with TCE and vinyl chloride monomer.

Contaminant descriptions and risk factors are available from the Agency for Toxic Substances and Disease Registry, an arm of the CDC.

Cleanup Progress

Occidental Chemical finished a study of the sites' contamination in the spring of 1993. In the summer of 1993, the EPA selected the approaches for site cleanup. The remedy focuses on two areas: the groundwater and the unlined earthen lagoons. The groundwater remedy involves extracting and treating groundwater using liquid phase carbon and air stripping ( forced air strips away the contaminants), paired with vapor-phase carbon absorption (the carbon removes any contaminants from the forced air stream), and long-term monitoring of the groundwater contamination. The groundwater extraction and treatment system is currently operating and is intended to operate until the groundwater contaminants are removed to the federal drinking water standards. The earthen lagoon remedy involved the excavation and off-site disposal of the residual PVC material in addition to excavating and disposing of a layer of crushed coal and underlying soil at the bottom of the earthen lagoons. Excavation and disposal of the lagoon materials was completed in September 2008. The area was backfilled and seeded and is now fully grown. The selected remedy also required additional sampling of a sediment pond and a drainage swale in the on-site portion of the flood plain.

In June 1994, EPA ordered the PRPs to design and carry out the cleanup for the site. The design for the groundwater remedy was finished in August 1997. Construction for the groundwater remedy began in March 1998 and was completed in January 1999. An evaluation of the groundwater treatment system was conducted by an EPA contractor in 2004. The report included recommendations to collect additional data in regards to the remedy. Occidental completed these activities in March 2006. Based on the results of the data collection, Occidental prepared a workplan to optimize the groundwater extraction and treatment system. The six-step optimization of the groundwater treatment system process has been completed. Groundwater continues to be pumped, treated and discharged. Discharged water continues to meet the PADEP NPDES requirements.

In November 2001, work was conducted to remove soil from a portion of a drainage swale located at the southwest portion of the site in the floodplain. A total of 200 tons of soil were excavated and sent offsite for disposal. After excavation, the drainage swale was backfilled with clean fill and the top foot was backfilled with rip-rap. For the cleanup of the earthen lagoons, two pilot studies were conducted. The tests were inconclusive so more investigation was needed and additional sampling was conducted. One new off-site well was also installed to obtain comparison data. The information collected as part of this sampling was used to conduct a risk evaluation in connection with the earthen lagoons. EPA then made a determination that a FFS was required to re-evaluate the remedial action previously selected for the earthen lagoons. On September 29, 2005, EPA and Occidental entered into an Administrative Agreement and Order on Consent to conduct the FFS. Occidental conducted the FFS activities as outlined in a workplan approved by EPA. As a result, an April 2008 ESD required the excavation and off-site disposal of the lagoon sludges. This work was completed in September 2008.

An Explanation of Significant Differences that changed the groundwater performance standard, added a contaminant to the groundwater contaminant of concern list, and described the site institutional controls was issued in 2013. The first 5-Year Review for the site was signed in August 2013. The only issue identified during the review process involves the implementation of institutional controls.


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