Former Use: The Site consists of a brick mill building (“Main Building”), an attached mill building annex (“Annex Building”), and the surrounding asphalt-paved parking areas. Two 500-gallon ASTs containing PCE and waste PCE were historically located outside on a concrete pad immediately adjacent to the east wall of the Main Building. The PCE was reportedly used in electrical resistor manufacturing processes. Both tanks were removed in 1988. Approximately 2,300 tons of CVOC-impacted soils were excavated from the vicinity of the former PCE AST pad in 2006. Since 1989, subsurface investigations conducted at the Site have consistently identified concentrations of PCE in groundwater orders-of-magnitude higher than the Department’s GW-2 Groundwater to Indoor Air Screening Level of 80 micrograms per liter (µg/L). Specifically, concentrations of up to 260,000 µg/L have been detected in groundwater immediately downgradient of the former AST pad in monitoring well MW-5, thus suggesting the potential for migration of CVOCs into the indoor air of the Site buildings through the vapor intrusion pathway. Sub-slab vapor sampling conducted in the basement of the Main Building in 2003 identified PCE at levels above the Department’s Residential Soil Gas Screening Level (68 micrograms per cubic meter [µg/m3]) in each of the five samples collected, with three of the samples also exceeding the Department’s Commercial Soil Gas Screening Level (100 µg/m3). Indoor air quality testing performed in the basement of the Main Building since 2003 has consistently identified concentrations of PCE exceeding NHDES’s Indoor Air Screening Levels (IASLs) for commercial and residential applications (2.1 µg/m3 and 1.4 µg/m3, respectively). As such, the vapor intrusion exposure pathway at the Site is considered complete.