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2.6.2 Previously Removed Underground Storage Tank(UST) The Environ Phase I and records obtained from the San Joaquin County Environmental Health Department indicated a 500 gallon gasoline UST was present at the Subject Property. The report indicated that the tank was removed from the ground in 1988. Based on review of the tank removal report and interviews with onsite personnel the location of the former UST is unknown and potential locations were covered with new construction which prohibited the installation of soil borings in those areas. No other issues were noted during Sage's research of the site information that would require further investigation. The sampling strategy Sage has included to address the Other Findings and De Minimis conditions identified would also identify other potential releases not identified in the Phase I report or other research. 2.7 Soil Sampling Procedures Sampling locations were selected based on historical site information and experience with similar properties. Soil sampling was performed using industry accepted methods and methodologies in the EPA Field Branches Quality Systems and Technical Procedures(EPA, 2008). Prior to initiation soil sampling activities, Sage contacted the Underground Service Alert(USA)to obtain clearance prior to subsurface drilling activities. Soil borings were performed using direct-push sampling techniques. The direct-push sampling technique utilizes a hydraulic system and percussion hammer to advance a 2.25- inch diameter sampling apparatus. Soil samples were collected continuously in 4-foot intervals as the borings were advanced. The samples were collected using an apparatus lined with a butylene tube that is pressed onto a properly decontaminated cutting shoe. This technique allows for rapid site assessment while also minimizing soil cuttings generated by the sampling operations. Before beginning soil boring activities and between soil sampling locations, all downhole sampling equipment was decontaminated in accordance with EPA guidelines to minimize the potential for cross- contamination between samples. Boring logs were prepared for each location and are located in the Appendix C. One Soil sample was collected using a hand auger from approximately 1.0 to 1.5 feet below ground surface in the vacant field located in the western portion of the Subject Property. Two sump samples were collected from approximately 8 feet below ground surface. The samples were collected using a clean scoop connected to an extension pole. 2.8 Sample Handling and Testing The samples were placed in appropriate containers, preserved in a cooler of ice at approximately 4°C,and delivered to Alpha Analytical Inc.,located in Rancho Cordova,California.Proper chain-of- custody procedures were followed throughout sample collection and handling. Sage Environmental Consulting,L.P. 2-3 Westlake Chemical Company July 2013 Lodi,CA,Phase II Investigation