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� St 15 November 2005 . AGE-NC Project No 95-0130 Page 2 of 10 south sections of the site, soil and ground water remediation equipment occupy the southwest section of the site A soil vapor extraction remediation system has been in operation at the site since August 2004, a ground water pump-and-treat remediation system has been in operation at the site since November 2004 2 2 UNDERGROUND STORAGE TANK REMOVAL It is AGE's understanding that two USTs were removed from the northeast section of the site circa 1988 Soil samples collected beneath the USTs detected total petroleum hydrocarbons quantified as gasoline (TPH-g) and benzene, toluene, ethylbenzene and xylene (BTEX compounds) at concentrations ranging from 22 milligrams per kilogram (mg/kg) to 2,200 mg/kg One 550-gallon gasoline UST and two 4,000-gallon gasoline USTs, dispensers and product piping were removed from the east section of the site on 01 September 1998 TPH-g was detected in soil samples collected beneath the former 4,000-gallon UST excavation area at concentrations as high as 8,200 mg/kg, BTEX compounds were detected at concentrations as high as 1,400 mg/kg The greatest benzene concentration was detected at a concentration of 6 3 mg/kg,methyl tert butyl ether (MTBE) was detected at concentrations as high as 13 mg/kg, tert-amyl methyl ether (TAME) was detected at concentrations as high as 0 29 mg/kg and tert butanol (TBA) was detected at concentrations as high as 5 1 mg/kg Total lead was detected in samples at concentrations as high as 32 mg/kg No other analytes were detected above laboratory reporting limits from the analyzed samples Results of the September 1998 tank removals were reported by AGE in Underground Storage Tank Removal Report, dated 09 August 1999 Analytical results of UST removal soil samples are summarized in Table 1 23 PREVIOUS SUBSURFACE INVESTIGATION The following is a summary of previous investigations at the site of the unauthorized release of fuel products to the subsurface • December 1994 - Five soil borings (B-1 through B-5) were advanced at the site near the former UST areas to depths of 65 feet below surface grade (bsg) Petroleum hydrocarbon- impacted soil was encountered in all five soil borings at depths between 10 and 65 feet bsg (Table 2) Results of the December 1994 investigation were reported in Preliminary Investigation and Evaluation Report (PIER), dated 10 April 1995,prepared by Geological Audit Services, Inc • Advanced GeoEnviranmental,Inc