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t { I 05'May 1997 - AGE-NC Project No 95-0139 ' Page 3 of 9 2 3 3 CONTINUING EXCAVATION On 17 and 18 August 1993,further excavation of the former UST location was performed at the site, Excavation was performed under the direction of Geological Audit Services, Inc (GAS) The excavation was expanded to approximately 40 feet by 50 feet and a depth of 14 feet bsg Approximately 1,000 cubic yards of soil were excavated from the former UST area in August 1993 Of the soil removed, 700 cubic yards were placed into "contaminated" stockpiles and transported under non-hazardous waste manifest to Forward Inc Landfill in Manteca, California The remaining R 300 cubic yards were placed into "clean" stockpiles and were used to partially backfill the, ' excavation on 07 and 08 September 1993 Seven- soil samples (TP-1 to TP-7) were collected from-the excavation Total petroleum ' hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d) were detected in samples collected from the north and east walls of the excavation Discolored soil was observed along the ,north wall from approximately 10 to 13 feet bsg A summary of the excavation procedures and Ifindings was included in the Quarterly Report- October 1993 prepared by GAS Analytical results of excavation soil samples are summarized on Table 1 On 08 September 1993, 14 samples (S=1, S-2 and S-4 to S-15) were collected from the stockpiled soil and analyzed for TPH-g, TPH-d and volatile organics (benzene, toluene, ethylbenzene and total Ixylenes, BTE&X) Excavation and stockpile sample locations are shown on Figure 3 Analytical results are summarized on Tables 1 and 2 Procedures and findings were summarized in a Quat terly Repot t - October 1993 prepared by GAS On 07 and 08 September 1993,approximately 300 cubic yard of"clean"stockpiled soil was returned to the excavation On 31 December 1993, the excavation was backfilled to surface grade using pea ' I gravel On 03 December 1993, two composite samples were collected from the stockpiled soil (SP- 16/SP-17 and SP18/SP19)and analyzed for 10 metals and halogenated volatile organic compounds Sampling was performed for soil disposal purposes Sample locations are illustrated on Figure 3 On 13 and 20 December 1993 and 03 February 1994, approximately 670,cubnc yards of stockpiled soil was transported to Forward Inc , for disposal Approximately 30 cubic yards of soil were left' ' on-site Two soil samples were collected from the remaining stockpile and composited for analysis (SP-20, SP-21) Petroleum hydrocarbons were not detected in the composite sample The soil was = subsequentlyused Sas surface fill material Procedures were summarized in a Quartet ly Report - IMarch 1994 prepared by GAS Analytical results of soil stockpile samples are summarized on Table 2 i 1 t s I I According to a 15 June 1994 letter issued by the PHS-EHD, on 21 April 1994, product and vapor piping associated with the former UST was removed from the site Three soil samples were collected a 1 1 I _1 1 ,