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chemical analysis at 26 feet and 36 feet from MW1, 30 feet from MW2, and 34 feet from MW3. On 19 March 1987, ground water was sampled from all three monitoring wells. All of the soil and ground-water samples were analyzed for benzene, toluene, xylene, ethylbenzene, and total hydrocarbons by Environmental Labora- tories. These results also are given in Table 3. The third onsite investigation was done by GTI (Bane and Taggart 1987) . On 3 June 1987, soil samples were obtained at approxi- t mately five feet below the soil pile surface with a hand-operated { auger. The samples were collected at six points from the pile and composited to form two samples. On 13 June 1987, Environ- mental Laboratories analyzed these two samples for benzene, toluene, xylenes, ethylbenzene, and total aromatic hydrocarbons. Again, the results are presented in Table 3. On 20 August 1987, EA conducted an investigation into possible offsite well water contamination in the vicinity of the Stockton station. Four domestic wells (Sample Numbers 1-4) hydrologically downgradient of the site and one well (Sample Number 5) up- gradient of the site were sampled (Table 4; Figure 6) . H. Knoll (personal communication 1987) of the San Joaquin County Health Services was consulted on the sampling sites and agreed that they were appropriate. Appendix A contains the well survey forms completed for the sample sites. At a location as close to the wellhead as possible, and ahead of any storage tank, a water sample was taken from the existing pipes. Prior to the sampling, the water line was run for 5 to 10 minutes to allow the plumbing to flush. The samples were sent to Brown and Caldwell Analytical Laboratories for benzene, toluene, xylene, and total hydrocarbon analyses. Table 4 summarizes the analytical results; these are included as Appendix B. In every case, hydrocarbons were below the detection limit (0.0005 mg/L for individual constituents; lmg/L for TPH) . 11 {