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19 October 2012 AGE-NC Project No. 97-0312 Page 5 of 22 rising groundwater levels had drowned the screen interval of UST-1.The pilot boring for UST-5 was advanced to a depth of approximately 74.5 feet bsg; the well screen of UST-5 was recorded as placed between 54.5 feet and 74.5 feet bsg. Laboratory `r analysis of soil samples collected at depths between 5 feet and 55 feet bsg from boring UST-5 detected petroleum hydrocarbons. • September 1997 - Six product USTs were removed from the site. A total of nine UST soil samples (T1-E through T6-17) and thirteen piping/dispenser soil samples (P1 through P13) were collected and analyzed. TPH-g and TPH-d were detected in the samples collected beneath the USTs at concentrations as high as 2,500 mg/kg and 32,000 mg/kg, respectively. TPH-g and TPH-d were detected in piping/dispenser samples at concentrations as high as 1,200 mg/kg and 16,000 mg/kg, respectively. Excavation of approximately 400 cubic yards of hydrocarbon- impacted soil was performed after removal of the USTs. Excavated soil was stockpiled on site. Procedures and findings were summarized in the UST Removal Report- September 1997 prepared by AGE. • November 1997 - On 22 November 1997, the stockpiled soil was spread to a thickness of approximately three feet. On 24 November 1997, a total of 16 samples were collected from the stockpiled soil and analyzed for TPH-g, TPH-d, benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary butyl ether (MTBE). TPH-g and TPH-d were detected in the samples at concentrations as high as 1,500 mg/kg and 4,100 mg/kg, respectively.Stockpile sampling was summarized in the AGE-prepared Quarterly Report-December 1997, dated 13 February 1998. • June 1999-Soil borings B14 through B17 and monitoring well UST-6 were installed at the site and soil and grab water samples were collected. The borings were advanced to further define the hydrocarbon-impacted soil plume; UST-6 was installed to delineate the northern extent of hydrocarbon-impacted groundwater. Borings B14 through B17 were advanced to a vertical depth of approximately 100 feet bsg; boring UST-6 was drilled to a vertical depth of 75 feet bsg. TPH-g was detected in samples B14-20 and B15-15 at concentrations of 570 mg/kg and 540 mg/kg, respectively.TPH-d was detected in six of the 24 samples analyzed (B14-20, B14-30, B15-15, B15-20, B17-25 and B17-40) at concentrations as high as 13,000 mg/kg (B14-20). Benzene was detected in sample B14-20 ata concentration of 4.1 ' mg/kg. Toluene, ethylbenzene and xylenes were detected in samples B14-20 and B15-15 at concentrations as high as 9.8 mg/kg.Other petroleum hydrocarbons were not detected in the 24 soil samples analyzed. MTBE was detected by EPA Method 8260 in samples B14-20, B17-25 and B17-40 at concentrations of 0.41 mg/kg, 12 mg/kg and 8.1 mg/kg, respectively. Tert-butanol (TBA) was detected in sample B14-20 at a concentration of 0.3 mg/kg. Other oxygenates were not detected in these three samples or in sample at onceStrat ons of 0.051 mg/kg and 5-15. TE was detected by EPA e0 54 thod 8020 in samples B14-30 and B1 - Advanced GeoEnvironmental,Inc.