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r <br /> t <br /> Chevron <br /> I A 1 Chevron <br /> tt �v� I r <br /> • 97 AI l; 15 PM <br /> Chevron Products Company <br /> August 12 1997 6001 Ballinger Canyon Road <br /> Building t <br /> San Ramon CA 94563 <br /> PO Box 6004 <br /> San Ramon CA 94583 0904 <br /> Mr Harlin Knoll <br /> San Joaquin County Public Health Services Marketing—Sales WestPhone 51 0 842 9500 <br /> 304 E Weber Ave Third Floor <br /> Stockton CA 95202 <br /> Re Clievron Station# 9-2033, 508 W Cliarter Way, Stockton, CA <br /> Attached UST Closure and Limited Overexcavahon Sampling Report (Touchstone 8/7/97) <br /> Attached Uniform Hazardous Waste Manifests(#'s 96430826 95784406 407,411 95894474 84) <br /> Dear Mr Knoll <br /> Please find attached a report dated August 7 1997, that was prepared by Chevron's consultant <br /> Touchstone Developments(Touchstone), to describe the field activities, sampling procedures and results <br /> that were associated with the removal of service station facilities during September through November <br /> 1996 <br /> On September 6 1996, all liquid UST contents and rinsate were removed and properly disposed of The <br /> removal of all subsurface equipment was performed on September 9, 1996 Touchstone was onsite to <br /> perform compliance soil sampling beneath the removed UST's, product piping, hoists and a lube bay <br /> floor sump Atl sampling was witnessed by W Eric Trevena, of your agency Copies of the hazardous <br /> waste manifests documenting the proper disposal of subsurface equipment and liquids removed from the <br /> subject site are attached for your reference <br /> The analytical results obtained from compliance soil sampling revealed the presence of motor fuel <br /> contamination beneath the fuel UST complex dispenser islands and hydraulic Hoist areas Based on these <br /> information, soil remediation by overe\cavation was performed according to Touchstone's Corrective <br /> Action Plan dated August 30 1996 The results of soil sampling at the limits of the overexcavation <br /> indicated residual levels of TPHGas up to 160 ppin in one location (sample OXB2 (0 10') The residual <br /> detections of benzene ranged between non-delect and 0 07 ppin The highest concentration (27 ppm) of <br /> residual MTBE was measured at 19' from beneath the former fuel UST complex The combined results of <br /> all remedial e\cavation sainpling serve to define the full extent of TPHGas/BTEX contamination in soil <br /> The full e\tent of MTBE contamination in soil appears to be defined except,for vertically within the <br /> fornier ftiel UST comple\ It is felt that the overe,,cavation activities were successful in removing all <br /> significant sources of groundwater contamination <br /> Touchstone's report also discusses the sampling and onsite remediation of soil stockpiles that were <br /> generated during overexcavation activities With the exception of approximately 150 cubic yards, all soil <br /> stockpiled at the subject site was successfully remediated and reused as excavation backfill material The <br /> remaining 150 cubic dards was transported to BFI Vasco Road Landfill in Livermore California for <br /> Proper disposal <br />