SITE INFORMATION AND CORRESPONDENCE

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CHRONOLOGY Ruth Strong Property 5157 W. Business Loop 205 Tracy, CA 95376 08/18/89 Six underground storage tanks (UST) removed this date under permit and inspection by the San Joaquin County Environmental Health Department (EHD). Soil samples for analysis were collected from beneath the tanks. Laboratory results reported petroleum hydrocarbon impact beneath the tanks. 09/13/89 Unauthorized Release Report and Notification of Hazardous Waste Discharge filed this date. 01/14/08 Site placed in Local Oversight Program on this date. 07/08/98 Fieldwork began this date to install six soil borings (B-1 through B-6) and four groundwater monitoring wells (MW-1 through MW-4). See Advanced GeoEnvironmental, Inc. (AGE) report "Preliminary Investigation & Evaluation Report" dated September 14, 1998. 05/30/00 Two groundwater monitoring wells (MW-5 and MW-6), and one soil boring (B-7) were installed. See AGE report "Second Quarter 2000 Groundwater Monitoring Report" dated August 9, 2000. 01/11/02 Two soil borings (B-8 & B-9) were advanced to total depth of 60 feet bsg for the collection of grab groundwater samples to investigate the vertical extent of the contamination. Minor detections of total petroleum hydrocarbons (TPH) as gas, TPH as diesel, ethylbenzene, toluene and xylenes were reported. No benzene was reported. See AGE report "Quarterly Report — First Quarter 2002" dated May 16, 2002. 10/30/02 Four groundwater monitoring wells (MW-7 through MW-10) were installed. See AGE report "Fourth Quarter 2002 Groundwater Monitoring Report" dated April 28, 2003. 03/05/04 Two groundwater monitoring wells (MW-11 & MW-12) were installed. See AGE report "First Quarter 2004 Groundwater Monitoring Report" dated August 27, 2004. 04/29/05 Date of "Problem Assessment and Feasibility Study" prepared by AGE in which they recommend excavation of contaminated soil and monitored natural attenuation of the groundwater as the most feasible remedial alternatives for the site. 05/30/06 Start date of site remediation by over-excavation of contaminated soil. Sidewall soil samples for laboratory analysis were collected on June 1, 2006, and the excavation was backfilled. In preparation for the work monitoring wells MW-1 and MW-2 were destroyed on 1120106; they were replaced after the work was completed. During excavation activities monitoring well MW-4 was damaged. It was subsequently overdrilled and replaced in the same location. See AGE report "Excavation and Sampling Report" dated December 1, 2006.