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/jClaytori 1. INTRODUCTION Clayton Group Services, Inc. ("Clayton") has prepared this report on behalf of Shell Oil Products (Shell) to present the information gathered during the recent limited vertical delineation of fill material that is present at the Shell Tracy Pump Station. The fill material investigated as part of this study is located in the western portion of the Shell Tracy Pump Station, located at 25705 S. Patterson Pass Road, in Tracy, San Joaquin County, California(Figures 1 and 2). The Tracy Pump Station was constructed in 1964. A 20-inch pipeline enters the property near its eastern border, and after passing through equipment for heating the crude oil, the pipeline exits the property near its northwestern corner. The fill material investigated comes from pipeline right-of-way construction activities, and the area is used for pipe and equipment storage. The site is surrounded by pastureland and the topographic slope is toward the east. Highway 580 is located approximately one-half mile to the east of the Site. Based on surface topography, groundwater flow is anticipated to be toward the east. Clayton's previous experience in the vicinity of the Site indicates that depth to groundwater is greater than 100 feet below ground surface (bgs). 2. SCOPE OF WORK Varying amounts of fill have been placed on the western portion of the property, and the investigation was performed to characterize the vertical extent of the fill and evaluate the fill for the presence of petroleum hydrocarbons. The purpose of this investigation was to conduct a limited assessment of the fill material on the property in preparation for an asset divestiture. Fill thickness is variable, from less than a foot to approximately 10.5 feet. Ten borings were advanced at the locations shown on Figure 2 to provide information on the fill material. 3. METHODS 3.1. PRE-FIELD ACTIVITIES Permits were obtained from San Joaquin County Environmental Health Department (SJCEHD). A site-specific environmental health and safety plan was prepared for the work, and was kept onsite during field activities. 3.2. SOIL BORINGS A private utility locator cleared each soil boring location on June 17, 2004. Drilling operations were performed by Gregg Drilling, Inc. of Martinez, California on June 21, 2004. A total of ten boring locations were hand cleared to 5 feet bgs. If the fill 1 material/native interface was not encountered within 5 feet bgs, the borehole was then continuously cored using a direct push drill rig. Soils were logged for lithological 5:\GS\PROJECTS\MIM 16 51,11 Tracy Pump Stmiw\R p n\100 M DOC 1