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GeoHydrologie Consultants, Inc. On July 1 ], 1995,the three (3)vadose wells(VWA, VWB,and VWC) and three groundwater monitoring wells(MW-1, MW-2 and MW-8) were properly abandoned prior to station remodeling activities. On July 25, 1995,five single-walled, steel USTs were removed from the Site and disposed of by Erickson of Richmond of California. Approximately 1,500 cubic yards of soil was removed from UST excavation and transported to Forward Incorporated, of Stockton, California for disposal.Nine (9) soil samples were collected beneath the five (5) USTs after excavation and seven (7) soil samples were collected at a depth of 2 to 4 feet beneath the product lines.TPH and benzene was detected in soil samples collected from beneath the USTs at concentrations up to 12,000 mg/kg TPH and 33 mg/kg benzene. On September 14, 1995 Thrifty contracted Alton Geoscience (Alton)to perform a vapor extraction test at the site to assess the possibility of using this technology for soil remediation. Results of the test indicated an effective radius of influence of approximately 33 feet with a flow rate of approximately 16.8 scfm and a pressure drawdown of approximately 0.10 inches of water(inches H2O);therefore, vapor extraction was identified as a feasible remediation option for the mitigation of hydrocarbon affected soil in the vadose zone beneath this site. From May 28 through 30, 1996 wells VW-2, VW-4, VW-5, VW-6, MW-IONW-I and MW-I INW-3 were installed onsite to depths ranging from 16.5 to 58.5 bgs. Monitoring wells MW-10/VW-1, and MW-1 I/VW-3 were installed as nested wells. Well VW-2 was completed as a dual-completion vadose zone monitoring well. Wells VW-4, VW-5,and VW-6 were completed as triple-completion vadose zone monitoring wells. In March 1999,groundwater was encountered at a depth of approximately 33 feet bgs during the installation of groundwater monitoring well MW-12. The hydraulic gradient was measured to be 0.0013 feet per foot to the southwest-southeast on March 31, 1999. Laboratory analysis of soil samples detected TPH concentrations from 1.4 mg/kg to 6,400 mg/kg,detected benzene concentrations from 0.26 mg/kg to 100 mg/kg,and detected MTBE concentrations from ND to 35 mg/kg.The presence of MTBE in the soil sample was confirmed at concentrations ranging from ND to 1.1 mg/kg by EPA Method 8260. The highest concentration of aromatic volatiles in soil samples were detected in the 50 foot bgs sample. Laboratory analysis of groundwater samples detected 21,000 µg/L TPH, 3,200 µg/L benzene, and 150 Rg/L MTBE. The presence of MTBE was confirmed using EPA Method 8260 at a concentration of 120 pg/L. In the surrounding groundwater monitoring wells,TPH was detected at concentrations ranging from ND to 760 µg/L, detected benzene concentrations from ND to 2.1 µg/L, and detected MTBE concentrations from ND to 540 µg/L. The presence of MTBE was confirmed using EPA Method 8260 at concentrations ranging from ND to 490 pg/L. TOC 172 UST Removal Report Final Page 4