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Results and Conclusions The quantitative analyses showed that the stained soils contained petroleum hydrocarbons at concentrations ranging from 2800 to 8900 mg/kg. Visual observations indicated that the stained areas are limited in size,and that samples collected immediately below the stains contain much lower concentrations of petroleum hydrocarbons(390 mg/kg at T-1-2 and 170 mg/kg at T-3-1). Petroleum hydrocarbons were not detected above the laboratory reporting limit in any of the other confirmation samples. The following conclusions can be drawn from the shallow soil sampling: • No impact to soil was observed or detected by quantitative analysis in the area of the large AST. • Limited areas of soil staining occur in the vicinity of the smaller AST. • Although petroleum hydrocarbon concentrations are elevated within the stained soil,they drop off rapidly outside the stained area. • The deepest soil staining observed was 6 feet below ground surface. Based on these findings it is CKG's opinion that the soil staining observed in the vicinity of the smaller AST is minor. Given that the soil has now been disturbed by the contractor's excavations and is exposed to sunlight and air,it is probable that natural degradation will reduce the concentrations over time. In addition,because the depth to groundwater is at least 70 feet below grade,there is little chance that the stained soils could impact groundwater quality. For these reasons CKG Environmental does not recommend further assessment or remediation activity at the site CKG recommends that Owens-Brockway submit this report and data to Ms.Wendy Cohen of the Regional Water Quality Control Board,Central Valley Region,and Mr. Steve Dalton,Fire Marshall c/o San Joaquin County Community Development Department,with a request to close the files on these ASTs. LIMITATIONS This report was prepared in general accordance with the accepted standard of practice,which exists in Northern California at the time the report was prepared. Conclusions and recommendations presented in this report are based on the results of the work completed. This scope of work includes quantitative analysis of nine soil samples conducted by McCampbell Analytical. Only work described herein was performed. As such CKG cannot render opinions on issues not resulting directly from the work performed. It should be recognized that definition and evaluation of environmental conditions is a difficult and inexact art. Judgments leading to conclusions and recommendations are generally made with an incomplete knowledge of the conditions present. More extensive studies,including additional environmental investigations,can tend to reduce the inherent uncertainties associated with such studies. AST Soil Sampling Report,Owens-Brockway Tracy 3 September 24,2002 CKG Environmental,Inc.