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Unocal Corporation <br /> b)versdied 6usinassog <br /> 2000 Grow Canyon Place.Sults 400 <br /> San Ramon.Calj(ornia 94583 <br /> Telephane(510)867-0760 <br /> Facstmiie(510)277-2308 <br /> UNOCAL 2iFILE O ?�i.^s <br /> RPT OPS TRANSMITTAL <br /> 2— 34 5 6 <br /> k February 7, 1971 <br /> West Req�on <br /> 6'v" manml Rvned;awn Semees Mir. Steven Sasson <br /> San Joaquin County Public Health Services <br /> Environmental Health Division <br /> 4 PO Box 388 <br /> -Stockton, California 95201-0388 <br /> Former Unocal Service Station#2859 <br /> 1665 Pacific Avenue <br /> Stockton, California <br /> Dear Mr- Sasson: <br /> This letter is to transmit the attached Renre4al Acdon Perfern we Sum R17-OcWber <br /> through December 1996 prepared by Pacific Environmental Group, Inc. for the above <br /> referenced site. The soil vapor extraction (SVE) system at the site was shut down on <br /> November 6, 1996 fallowing a long-term pilot test, and the attached report provides the <br /> final round of monitoring data from the test: <br /> I would also like to <br /> take this o ottani <br /> to res and to <br /> pp tY p your letter of January 9, 1997. In <br /> that letter, you recommend that additional assessment be performed and that a feasibility <br /> study and corrective action plan be prepared for the site. Please consider the following; <br /> 1) All underground storage tanks and product piping have been removed <br /> In 1988, 1,100 cubic yards of hydrocarbon-impacted soil were removed <br /> from an excavation under the tank pit area. The excavation extended to <br /> groundwater which was encountered at a depth of 30 feet. Sn addition, <br /> about 2,745 pounds of gasoline and 12 pounds of benzene were <br /> removed by the SVE system from the dispenser island area. The <br /> majority of the source of contamination has been removed. <br /> 2) Depth to groundwater has fluctuated over the years from 30 feet bgs in <br /> 1988 to over 50 feet bgs in 1990 through 1992. This smear zone was <br /> largely submerged during the operation of the SVE. The SVE system <br /> was properly designed and operated well. Unfortunately, the system <br /> was not able to impact contaminated soil located below the <br /> groundwater. Based on recent weather patterns,I do not anticipate any <br /> Significant drop in the lev J of groundwater in the near figure. <br /> EXHIBIT 3 <br /> 600 'd 602Z LZZ 019:131 311 HISON IN33 IVOO D 19: t MA)L6 ,90- NV <br />