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Hazardous Waste Cleanup: SGS-Thomson Microelectronics in Montgomeryville, Pennsylvania

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Cleanup Status

EPA plans to collect groundwater samples in the winter of 2019 to further assess both the groundwater and vapor intrusion pathways at the Facility. Current Human Health and Migration of Contaminated Groundwater Environmental Indicator Determinations will be made once this data is analyzed.

Cleanup Background

During closure of former solvent storage tanks in 1990, volatile organic compounds (VOCs) were discovered in the site soils and groundwater in the general vicinity of the tanks. Contaminated soils were excavated in 1994 and a groundwater monitoring program was initiated. The facility received a release of liability for soils from Pennsylvania Department of Environmental Protection (PADEP) in January 1997 since the analytical data indicated that the Statewide Health Standards had been met. The facility received a release of liability for groundwater from PADEP in February 1997 by virtue of attainment of the site specific standards. Trichloroethylene (TCE) and vinyl chloride remained above PADEP’s medium specific concentrations for groundwater but a downward trend in concentrations was apparent and no registered potable wells were located in the vicinity of the facility.

A Daycare is located approximately 500 feet northwest of SGS. In December 2010 and July 2011, EPA’s Superfund program collected sub-slab, indoor air and ambient air samples at the Daycare to determine if the remaining groundwater contamination at SGS was migrating and contributing to potential vapor intrusion inside the Daycare.  No constituents of vapor intrusion concern attributable to SGS were detected in any of the samples collected during either round of sampling. Superfund concluded that the vapor intrusion pathway is likely not a completed pathway at the Daycare.

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Site Description

Interactive map of SGS-Thomson Microelectronics, Darby, PA

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The facility was owned and operated by Advanced Power Technology RF and Microsemi RF between 1993 and 2007. Silicon-based semiconductors in the product area of transistors were historically manufactured at this location by the companies. K & B Wireless Communication currently occupies the facility.

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Contaminants at this Facility

Potential vapor intrusion of chlorinated organic compounds, primarily trichloroethylene (TCE), in the on-site Facility building needs to be further assessed. While there has been evidence of natural attenuation of these types of compounds in groundwater, groundwater monitoring has not occurred since 2006. EPA plans to collect groundwater samples in the summer 2014 to further assess both the groundwater and vapor intrusion pathways.

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Institutional and Engineering Controls at this Facility

A deed restriction that prohibits groundwater use at the Facility was required as part of the release of liability granted by PADEP. EPA will determine whether any additional controls will be required.

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Land Reuse Information at this Facility

The site's future use is yet to be determined.

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Site Responsibility at this Facility

Resource Conservation and Recovery Act (RCRA) Corrective Action activities at this facility have been conducted under the direction of EPA Region 3 with assistance from PADEP.

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