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r CHRONOLOGY 4445 PERSHING AVE., STOCKTON LOP SITE CODE: 1785 CVRWQCB CASE #390484 APN-110-180-06 06/25/87 A 550 gallon waste oil UST (#4) was removed and soil samples collected beneath it. Soil sample results showed contamination so two additional phases of soil removal and confirmation sampling were done. TPHg, TPHd,nor BTEX were detected in the soil sample collected from the final excavation. 10/03/89 A Pre-UST Removal Assessment was performed. Soil borings were completed in 12 locations, but samples were analyzed from only 8 of the locations (B1-B8). Contamination was not evidenced in the area outside of the Iocation of the existing USTs that were scheduled for removal. 05/30/90 Four gasoline USTs (#1,2,3 and 5) were removed and approximately 70 cubic yards of contaminated soil were removed for disposal. Soil samples were collected beneath the tank inverts and piping trenches. TPHg and BTEX were detected; sample T2-S being the most contaminated location sampled. Three new double walled USTs were installed in a non- contaminated area north of the fueling islands. 07/09/90 Three groundwater monitoring wells (MW)were installed. 07/10/90 Two vapor extraction wells were installed: one northwest and one southeast of the area T2-S. 12/05/91 A soil vapor extraction pilot test was initiated. 12/27/91 One additional MW was installed. 01/14/92 The soil vapor extraction pilot test was terminated. 01/92-9/02 Quarterly monitoring and sampling of the monitoring wells was performed. 09/27/02 EHD reviewed No Further Action/Request for Closure Report prepared by Cambria dated September 17, 2002. TPHg and BTEX have not been detected in the groundwater from the monitoring wells since August 1999. MTBE above 5 ppb has not been detected since May 1999. EHD will request no further action concurrence from the CVRWQCB. HK/Chron4445pershing