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S G Dr Color Spot„ Inc. 2 f;:ww June 28, 1991 (M88168G) The SGD obser, er arrived at the site at 0930 on May 22, 1991, at which time JTO had already removed the product delivery lines, vent lines, and fill ports and had exposed both tanks. By 1100, both USTs were removed and appeared to be free of holes. Excavated soil was stockpiled ar:-and the north, west, and south sides of the excavation. No visible staining or hydrocarbon odor was noted in the soil piles or tank excavation. The soils removed from the excavation were monitored by SGD for volatile petroleum hydrocarbons using a photoionization detector (PID). The PID, a Microtip II HL-200 model manufactured by Photovac, Inc. , was calibrated that morning to an isobutylene gas standard of 50 parts per million (ppm) provided by the Alphagaz Corp. (lot number 30689). The ambient air was monitored before and during tans: excavation and did not contain vapors detectable to the PID. The soil piles were monitored in 10 different locations by exposing soil several . inches below the surface and holding the PID probe within 3 inches of the soil. During this monitoring, no volatile hydrocarbons were detected by the PID. The area of the tank excavation was approximately 30 by 32 feet, and the depth was between 10 and 12 feet (see Figure 3 - Plan View of Excavations). Three underground utility lines were partially exposed along the east side of the excavation. These lines (one metal and two PVC) are approximately 3 inches in diameter and buried between 2 and 3 feet deep. Four soil samples were collected from beneath the former tank locations, one sample from each end as shown on Figure 3. Each sample location was cleared of sloughed soils and deepened to about 14 feet prior to sample collection. The samples were collected in pre-cleaned stainless steel sleeves (2.5 inches in diameter, 3 irches-long) from the tooth-portion of the backhoe bucket. The sample sleeve was pushed into the soil and carefully removed so that the sleeve remained full of soil. The ends were covered with Teflon sheeting and plastic caps, taped, labeled, and placed in an ice chest with ice and artificial ice pending delivery to the laboratory for chemical analysis. Ms. Resch of EHD directed the collection of a fifth soil sample, from beneath the product lines 2 feet from the southwest corner of the building housing the boiler (Figure 3). The sample was collected from a depth of 3 feet bgs. Soil in that area was stained, contained a strong hydrocarbon odor, and registered up to 100 ppm on the PID readout. The sample was collected by pushing a sleeve (as described above) into the side wail of a hole about 2 feet in diameter and 4 feet in depth, excavated by shovel. This sample, labeled number 5, was handled in the same manner as the first four. Table 1 - Soil Sample Analytical Results, contains the results for all soil samples collected on May 22 and the reports are included in Appendix A - Laboratory Analytical Reports. The results are discussed in the Laboratory -- -- -------Analysis-section-of this--letter-report-- Observations--recorded during-field have been included in Appendix B - Field Memoranda.