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a Stantec PHASE II ENVIRONMENTAL SITE ASSESSMENT REPORT Introduction March 31,2011 The Phase I ESA reported that Calpine used halogenated solvents in a former parts washer that was located in the southwestern portion of the southern warehouse. The parts washer was removed and the use of halogenated solvents was terminated. 1.2 SITE TOPOGRAPHY A review of the United States Geological Survey Lockeford, California Quadrangle Topographic Map indicates the Site is situated at approximately 55 feet above mean sea level and the local topography is sloped gently to the southwest. 1.3 REGIONAL GROUNDWATER Based on the GeoTracker website, the nearest site with available information on soil and groundwater is located approximately 1,500 feet southwest of the Calpine Site. The GeoTracker site is identified as Valley Pacific Petroleum Services, 930 Victor Road, and is identified with the GeoTracker global identification number SL375213641. Based on the recent 2010 data for this site, the upper 10 feet of soil is a gravely silt with sand (ML). Groundwater is located approximately 55 to 59 feet below the ground surface (bgs) at that location and the groundwater gradient is to the south at less than 0.01 feettfoot. Based on the Valley Pacific Petroleum Services groundwater information, groundwater beneath the Calpine Site would be approximately 45 to 49 feet bgs. 1.4 SCOPE OF WORK The Phase II ESA was performed to evaluate the potential for subsurface soil and soil vapor impacts on the Property that may have resulted from historical activities on the Site or nearby properties. The scope of work included the following activities: • Pre-field planning including development of a Work Plan and a Site-specific Health and Safety Plan (HASP), boring location and utility clearance by both public and private services, determination of purge rates and volumes, coordination and scheduling of subcontractors, securing of necessary field equipment, and coordination with property owner representatives, as needed. • Established a Master File Record with San Joaquin County Environmental Health Department and obtained the necessary well permits for the proposed soil vapor boreholes that were advanced as part of the Phase II ESA work. A copy of the well permit is included in Appendix A. As part of the County's oversight for this project, San Joaquin County requires a copy of this report. • Advancement of 6 soil borings to a maximum depth of approximately 5 feet bgs within the areas of concern at the Site including within the buildings, near the former parts washer, and along the sewer lateral (Figure 2). • Collect soil samples between 4.5 to 5 feet from all the boreholes and submit the soil samples to the analytical laboratory. Selected soil samples were analyzed and the remaining samples were placed on hold pending the soil vapor analyses. i:\projects\calpine\lodi\report\lodi.svrpt.doc 1.2