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Tyson's Dump

Current Site Information

EPA Region 3 (Mid-Atlantic)

Montgomery County
Upper Merion Township

EPA ID# PAD980692024

7th Congressional District

Last Update: November 2014

Other Names


Current Site Status

The Tyson's Dump Site is currently in the Operation and Maintenance and Long-Term Monitoring Phase. The multiple remedies at the Site were fully constructed by 1997. The remedies include a wet soil cover to control the upward migration of vapors, a groundwater extraction system to prevent contaminated groundwater from entering the Schuylkill River, and another series of groundwater extraction wells to contain the deeper contaminated groundwater. The groundwater is treated on-site and is regularly monitored. The wet soil cover is also regularly maintained and monitored.

In August 2012, EPA issued an Explanation of Significant Differences (ESD) to document the selection of an alternative location for the groundwater recovery wells that initially were to be installed on Barbadoes Island as part of the 1990 Record of Decision (ROD) for Operable Unit 3 (OU-3). The 1990 ROD stated that if another location was selected for the Barbadoes Island recovery wells based on additional data to be collected, EPA would issue an ESD documenting this change. Based upon additional data collected subsequent to the issuance of the 1990 ROD, it was determined that one recovery well was necessary on the south bank of the Schuylkill River rather than on Barbadoes Island. This well was installed and began pumping on February 9, 1998.

EPA recently reviewed the site conditions and protectiveness of the remedies as part of the fourth Five-year Review (PDF) (62pp, 399 K, About PDF) that was conducted in 2014.

Site Description

The Tyson's Dump Site, located in Upper Merion Township, Montgomery County, Pennsylvania, is a four-acre abandoned sandstone quarry. The unlined lagoons were used to dispose of septic and chemical waste from 1962 to 1970. In the 1970s, sludges and liquid wastes, primarily chlorinated and other organic solvents, were dumped into the lagoons.

The state of Pennsylvania ordered the facility closed in 1973. During closure, the lagoons reportedly were emptied of standing water, backfilled, vegetated, and the contents transported off site, although contaminated soils remained on site.

In early 1983, EPA received a citizen complaint about noxious odors emanating from the site. An investigation indicated that the lagoon area soils and groundwater beneath the site were contaminated with organic solvents such as trichloropropane. Among the emergency actions, EPA erected a security fence, leachate was collected and treated, and a partial soil cap was placed over the lagoon area.

The contaminated groundwater had migrated beyond the site boundary in the direction of the Schuylkill River. Water intakes for Norristown and Philadelphia are downstream from the site on the Schuylkill River. An estimated 26,000 people live in the residential area surrounding the site.

Site Responsibility

This site is being addressed through a combination of federal, state, and potentially responsible parties' actions.

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 (NPL). This site was proposed to the NPL on September 8, 1983 and formally added to the NPL September 21, 1984.

Threats and Contaminants

Groundwater and soils on the site are contaminated with organic solvents such as trichloropropane. Contaminants from the site were detected in the Schuylkill River and in the groundwater beyond the boundary of the site.

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

Cleanup Progress

In 1988, the potentially responsible parties (PRPs), Ciba-Geigy Corp., Wyeth Labs Inc., Essex Group Inc., and SmithKline Beckman Corp., entered into a consent decree with EPA to address the contamination at the site.

In accordance with a Record of Decision (ROD) issued by EPA in March 1988, a soil vapor extraction (SVE) system was constructed to address the contaminated lagoon area soils. The SVE system operated from November 1988 to September 1996. During that time, approximately 200,000 pounds of organics were removed from the soils. However, it became apparent the SVE system was limited in its effectiveness to achieve the cleanup goals established in the ROD.

As a result, EPA requested that the PRP conduct a Feasibility Study (FS) to determine if another remedy could be implemented to address the contaminated soils. Based on the FS, EPA issued a ROD in July 1996 and selected a remedy to cover the site with a wet soil cover. The wet soil cover is an innovative technology consisting of a low permeability layer which maintains nearly saturated conditions to control and eliminate upward migration of vapors. Construction of the wet soil cover was completed in August 1997.

In 1989 a series of groundwater extraction wells were installed along the south bank of the Schuylkill River to prevent contaminated groundwater from entering the Schuylkill River. The groundwater is treated on-site. Since the groundwater treatment started operating in May 1990 site-related contaminants have not been detected in the Schuylkill River.

As a result of a ROD that was issued in 1990, the PRPs completed additional studies on the groundwater in the deep aquifer. The study determined that additional extraction wells were necessary to contain the contaminated groundwater plume. The extraction wells were installed in December 1997 and the groundwater is also treated on-site. EPA documented the completion of the wet soil cover and the groundwater treatment system in a Preliminary Close-Out Report (PCOR) in December 1997.

The PRPs continue to operate and monitor the wet soil cover and the groundwater pump and treat system. EPA reviewed the site conditions and issued a five-year review report in September 2009. EPA found the site remedy to be protective of human health and the environment. The next five-year review is underway now and will be completed by September 2014.


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