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' Report Buffalo Tank Corporation July 15, 1993 -2- Page -2- A second evaluation of the analytical results was performed by the laboratory at the request of the County Inspector. The ' revised laboratory results submitted by McLaren Laboratory stated that a "dilution was required due to heavy late eluting matrix interference; possible diesel" . ' Two additional soil samples were obtained by Canonie Environmental from an unknown location and results were submitted ' to the County in April 1990 . Samples were tested for volatile organics, BTEX, total volatile hydrocarbons, and volatile organics . Toluene was detected at a concentration of 0 .035 mg/kg. No further work has been conducted at the site. ' 2 .0 Fieldwork ' The backfill was removed from the original tank excavation to a depth of approximately 11 feet. The backfill was yellowish- brown, fine to coarse grained sand. During the excavation, the ' soil was field screened with an organic vapor analyzer (OVA - flame ionization detector) at various depths . No organic vapors were detected in the backfill . The OVA has a detection limit of M 1 part per million (ppm) . One ( 1) soil sample was collected from the backfill at a depth of approximately 6 feet for laboratory analyses (sample I .D. 675-fill-6 ) . ' At the 11 foot depth, native yellowish-brown, silty, clayey, fine grained sand was encountered. Strong petroleum odors were noted in the native sand. The T-shaped excavation was enlarged ' to a total depth of approximately 22 feet below the ground surface. OVA readings of 5000+ ppm were detected at approximately 17 and 22 feet below the ground surface. Seven (7 ) ' soil samples were collected at various depths ranging from 17 to 22 feet from the native soil for laboratory analyses (see Figure 2, Appendix A for sample I.D. 's and locations) . The last number in each sample I.D. indicates the depth at which the sample was ' collected. Excavation was terminated in order to assess the data collected and to review options for additional site investigation and remediation. Four (4 ) stockpile samples were collected for ' laboratory analyses (Figure 2 , Appendix A) . Each soil sample was collected by driving a clean brass tube into freshly exposed soil . The soil samples were sealed with ' teflon tape, capped, wrapped with duct tape, labeled, and placed in a cooler chilled with Blue Ice for storage. The soil samples were hand delivered under chain-of-custody procedures to ' GeoAnalytical Laboratories in Modesto, California. The soil samples collected from the stockpile and the backfill and the samples collected beneath the former location of T2 at 17 .5 feet akliw ' CONDOR