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I I Harding Lawson Associates facility in San Francisco, California. The tank was subsequently steam-cleaned, cut, and rendered harmless by H&H and disposed of as scrap metal at Levin Metals Corporation, in Richmond, California. Visual observations and organic vapor measurements taken using a photoionization detector (PID) indicated that backfill materials (sand) formerly I surrounding the tank did not appear to contain petroleum hydrocarbons; PID measurements were generally below 5 parts.per million (ppm). Localized pockets of backfill materials in the vicinityfthe-dispenser o island and a portion of the piping trench contained hydrocarbon odors; PID measurements of these localized pockets L. ranged from 30 to 100 ppm. Native soil surrounding the tank backfill materials consisted of very stiff, dark f gray, silty clay of high plasticity from the surface (underneath the asphalt-pavement section) to a depth of 4 feet. This soil graded to a stiff, brown, sandy clay of moderate plasticity to depths of a least 14 feet. Visual inspection and PID readings of native soils adjacent to the tank excavation and piping soils did not indicate the presence of petroleum hydrocarbons, with the. exception of the odors noted in the fill. Soil samples were collected from the native soil 2 feet below the backfill/native soil interface on the floor of the excavation using a backhoe. The soil samples were collected from the backhoe bucket in clean brass tubes, labeled, capped with aluminum foil and plastic caps, and sealed with electrical tape. Samples were stored in a chilled container and transported for analysis to NET Pacific in Santa Rosa, California, a state- certified laboratory. 9 Two soil samples were collected from native soil beneath the bottom of the I f former tank. Samples were collected from each end of the excavation and were T19461-H 6 of 20