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Commodore Semiconductor Group
EPA Region 3 (Mid-Atlantic)
EPA ID# PAD093730174
7th Congressional District
Last Update: January 2015
Commodore Business Machines
Current Site Status
The U.S. Environmental Protection Agency is overseeing current cleanup activities at the Commodore Semiconductor Group site by the Potentially Responsible Party (PRP), Rockwell Automation formerly known as Allen-Bradley, LLC. The remedy for the site included, among other things, a groundwater pump and treat system and the extension of an existing waterline to twelve residences along Rittenhouse and Audubon Roads. The waterline extension was turned over to the Audubon Water Company. Construction of a groundwater treatment system was completed in August 2000. The groundwater system currently pumps and treats approximately 10 gallons per minute of contaminated groundwater. Rockwell conducts groundwater sampling semi-annually to monitor the effectiveness of the groundwater treatment system. In light of recent groundwater data, Rockwell will be performing a plume stability analysis at the Site.
In September 2010, EPA completed the Second Five-Year Review of the remedy and found that the implemented remedy is protective in the short-term as there is no current exposure to Site COCs. Long-term protectiveness of the remedy will be achieved by continuing to pump and treat the groundwater, implementing institutional controls with regards to redevelopment and potential vapor intrusion on the Site, and maintaining effective institutional controls until cleanup standards are achieved.
An Explanation of Significant Differences (ESD), issued on September 28, 2011, added institutional controls (ICs) to the remedy in order to prevent human exposure to vapor intrusion of contaminants from groundwater at the Site. The ICs will require assessment for vapor intrusion in the event that the current building on-site is renovated and reoccupied or in the event that new buildings are constructed on-site.
Site DescriptionThe Commodore Semiconductor Group site, which is located in Norristown, Montgomery County, Pennsylvania was operated as a computer chip manufacturing facility from 1970 to 1993 by Commodore Business Machines. Waste solvents were stored in an underground concrete storage tank on site until 1975, when it was taken out of service. An unlined steel tank was installed next to the concrete one in 1975. Inspections conducted by the Pennsylvania Department of Environmental Protection indicated that both tanks leaked. The majority of residences in the area are connected to a privately-owned public water supply, however, a small number of individuals still have operational private wells.
- Site Responsibility
- Cleanup of this site is the responsibility of federal and state governments, and parties potentially responsible for site contamination.
- NPL Listing History
- This site was proposed to the National Priorities List of the most serious uncontrolled or abandoned hazardous waste sites, requiring long-term remedial action on January 22, 1987. The site was formally added to the list on October 4, 1989.
Threats and ContaminantsOn-site groundwater is contaminated with high levels of trichloroethylene (TCE) and other VOCs from the waste solvents that leaked from the underground storage tanks. TCE was also found in on-site soils but not at levels of concern. Accidental swallowing or contact with contaminated groundwater on the site may pose health risks, however, exposure pathways to this underground water have been removed.
Contaminant descriptions and risk factors are available from the Agency for Toxic Substances and Disease Registry, an arm of the CDC.
In 1981, Commodore excavated soils and pumped water from a contaminated well, then sprayed it onto surrounding fields. The VOCs dissipated into the air. Since 1984, air strippers have been in use to remove solvents from the groundwater. Air strippers have been installed on all affected public wells through agreements between Commodore and the local water authority. Also in 1984 household carbon units were installed at residences where at least 1 part per billion of VOC was detected. Other work done at the site included, groundwater extraction and treatment, extension of the existing water line to affected residences, and continued maintenance of hold house carbon units. On June 29, 1993, EPA issued a unilateral order to Commodore Business Machines, and Allen-Bradley Corporation to carry out this work. Only Allen-Bradley Corporation has complied with the order. Commodore Business Machines went bankrupt.
The waterline extension and laterals to the residences were completed in January 1997. Transfer of the ownership of the waterline extension from Allen Bradley Corporation to Audubon Water Company was completed in December 1997. The connection of the residences and the closing of the residential wells began in January 1998.
Construction of the groundwater extraction and treatment system began in the Fall of 1999. In February 2000, pipelines and underground wiring were installed, pumps were installed at each of the extraction wells, and the treatment building was constructed. The treatment process equipment was installed in May 2000. Preliminary start-up and testing of the system began in August 2000.
In September 2003, Rockwell Automation completed additional work to enhance and speed up the groundwater treatment. This enhanced treatment (ET) included the installation of a full-scale vapor extraction system to remove chemical vapors from the soil and bedrock, and chemical oxidation to treat residual contaminant levels in soil near and beneath the building. Rockwell continues to coordinate with EPA and PADEP and intends to accelerate cleanup.
In January 2007, the Audubon Water Company stopped accepting treated water from the groundwater treatment system. Rockwell Automation currently sends treated water to the sanitary sewer system and therefore has changed the groundwater system's pumping rate to 10 gallons per minute. Semi-annual groundwater sampling shows that the treatment system is maintaining capture of the contamination. Rockwell is in discussion with Lower Providence Township and PADEP regarding beneficial reuse of the treated water. The groundwater treatment system can resume pumping at full capacity once the plan for the alternate discharge location is finalized.