EPA Superfund Site

NORTH PENN - AREA 5

PA | EPA ID PAD980692693

About this site’s exposure pathways: As of May 2025, there is insufficient information to make a site-wide human exposure control status determination at the North Penn - Area 5 Superfund Site. The Potentially Responsible Party (PRP) is performing a vapor intrusion (VI) investigation in the onsite structure at Operable Unit 2 (OU2). Initial results indicate that there are elevated concentrations of volatile organic compounds (VOCs) in the sub-slab and at concentrations near action levels in indoor air, but concentrations are variable. Additional sampling is necessary to assess the seasonal variability of the potential vapor intrusion. This building was sold and is currently empty. A comfort letter has been issued for a VI mitigation system to be installed in the existing building and a VI mitigation system to be installed in any new building prior to use. VI sampling prior to building occupation is necessary to confirm the efficacy of the installed mitigation system. In addition, the Operable Unit 1 (OU1) groundwater VOC plume has been defined enough to allow for design of the remedy in the 2016 Record of Decision (ROD) Amendment, however, the OU2 groundwater VOC plume is not yet fully delineated.

EPA anticipates that there will be sufficient information to make a human exposure evaluation following the completion of additional VI sampling and further delineation of the OU2 groundwater VOC plume by December 2028. In the interim, EPA should be consulted prior to the occupancy of the existing building or any new buildings for potential VI issues.