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Therefore,in consultation with Mr. Sasson, H&A terminated the inv stigation and directed the backhoe operator to obtain a scoop of fresh soil from tht floor of the excavation. After Upgradient Environmental collected a sample fron i the bucket, the backhoe filled the excavation with imported pea gravel and the exca ated soil was transported to REMCO in Richmond, California for treatment. Sample CM-1-13' was transported to Sequoia Analytical and analyzed for Total Petroleum Hydrocarbons as gasoline (TPH-g) and benzene, toluene, ethylbenzene, and xylene (BTEX). The laboratory reported weathered gasoline in the C6-C12 range, with all analytes present except benzene (Table 1). Upgradient Environmental submitted a report of the - investigation to PHS/EHD the following month.No further work was requested by Stockton Mortgage or H&A. Sometime after 1995, San Joaquin County obtained the property frot a the trusts that had held the first mortgage. Recently, the County offered the property in an auction sale and it was purchased by Mr. Henry. 3.0 PROCEDURES The planned scope of-work was to drill one boring to an estimated d pth of 50 feet through the former tank cavity to determine the maximum vertical e tent of soil contamination, and three borings in a triangular pattern around it to ssess the lateral extent of contamination, including one boring to 80 feet to collect a vater sample. However, this plan was altered while drilling the first boring(CM1)through the tank cavity. Soil samples collected from this boring indicated that hydroc irbons were still present at high concentrations at 50 feet, so the driller was instructed to continue drilling until the lower limit of contamination was reached. This occurred at the approximate depth of the static groundwater level (90 feet), and'a water sample was collected. This made it possible to eliminate the deep boring east of the tank cavity, and also provided an indication of the magnitude of the problem. Therefore, only one add tional boring was drilled. Boring CM2 was drilled 25 feet south of the excavation(Fig e 2).This is 10 feet farther south than planned. The location was moved because the,big organic vapor readings obtained from CM 1,samples suggested that the extent of c ntamination might be greater than originally anticipated. V&W Drilling of Rio Vista, California used a Mobile Drill B-61 ho low-stem auger rig to drill the borings. Soil samples were collected at 5-foot intervals, beE inning at a depth of 15 feet in CMI and 10 feet in CM2. The samples were screened for he presence of organic vapors with a portable photo-ionization detector(PID), pres rved in a cooled ice chest for later laboratory analysis, and described on the boring log( ppendix A). A disposable plastic bailer was lowered through the augers to collect a water sample before CMl was abandoned. Both borings were backfilled by pumping cement-bentonite grout through a tremmie pipe. Drill cuttings were stored on plastic sheeting near the eastern property line. Twelve soil samples and the water sample were shipped to McCain bell Analytical Laboratory in Pacheco,where they were analyzed for TPH-g, MTB (methyl tertiary 3