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19 October 2012 AGE-NC Project No. 97-0312 Page 4 of 22 12,000 mg/kg, respectively. Petroleum hydrocarbon-impacted soil extended to a depth of approximately 50 feet bsg near the fueling island location. Soil boring locations are depicted in Figure 2. • September/October 1990-One groundwater monitoring well (UST-1)was installed on-site to a depth of approximately 102 feet bsg to determine if petroleum hydrocarbons had impacted groundwater. The screen of UST-1 was installed overlapping two coarse-grained intervals and may provide a vertical pathway for migration of impacted groundwater. Laboratory analysis of soil samples collected from the UST-1 boring contained detectable concentrations of petroleum ., hydrocarbon compounds to a depth of at least 85 feet bsg. Laboratory analysis of the initial groundwater sample collected from UST-1 also indicated the presence of hydrocarbons. TPH-g, TPH-d and benzene were detected at concentrations of 330 +� micrograms per liter (Ng/1), 880 pg/I and 4.5 pg/I, respectively. • September/December 1992 - Groundwater monitoring was performed during the third and fourth quarter of 1992 at the site. High concentrations of petroleum hydrocarbons were reported in the groundwater samples during both monitoring events. According to ESE documents, free product was pumped from UST-1 prior to sampling during both quarters. • 1993 - The well box for UST-1 was found to be in poor condition, and evidence of infiltration of water and fuel from the surface was noted; floating free product was encountered in UST-1. Groundwater monitoring and sampling were performed during the second, third and fourth quarters of 1993. Additionally, weekly groundwater extraction was performed as interim remediation. It was reported by ESE that water quality improved due to pumping activities. Interim pumping was reduced to biweekly beginning in 1994. • March 1995 - Three additional groundwater monitoring wells (UST-2, UST-3 and UST-4) were installed on-site to delineate the petroleum hydrocarbon impact to groundwater. Pilot borings for the three wells were advanced to 85 feet bsg; well screens were recorded between 65 and 85 feet bsg. Laboratory analysis of soil samples collected from the pilot borings detected petroleum hydrocarbons in samples from boring UST-4, located southeast of the area of concern, at depths of 25 feet, 30 feet, 35 feet, 40 feet and 45 feet bsg. Hydrocarbon compounds were not detected in any of the soil samples analyzed from borings UST-2 and UST-3, defining the maximum horizontal extent of impacted soil in the northwest and northeast directions. Initial groundwater sampling during the second quarter of 1995 contained low concentrations of TPH-g and TPH-d in samples collected from UST-4. • June 1997- One groundwater monitoring well (UST-5) and soil vapor well (VP-1) were installed on-site to assess shallow groundwater near the former UST area; u Advanced CeoEnvironmental,Inc.