SITE INFORMATION AND CORRESPONDENCE

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I Silgan Container Corporation - 2 - 22 March 2004 1815 Navy Drive, Stockton, San Joaquin County In a conference call on 3 January 2001 with Silgan and Caporale Consultants,Inc.,their consultant, Regional Board staff requested a resumption of quarterly groundwater monitoring, abandonment of damaged monitoring well GW-1, and installation of additional downgradient wells to determine the vertical and lateral extent of the chlorinated solvent plume. In a letter dated 23 April 2001,Regional Board staff requested a status report from Silgan by 28 May 2001. A Confirmation Sampling Report was received on 20 July 2001. On 15 October 2001, Silgan requested site closure. Regional Board staff responded in a letter dated 29 November 2001,that directed Silgan to complete the fourth quarter of 2001 groundwater monitoring event, submit a workplan to destroy damaged monitoring well GW-1,define the extent of groundwater contamination, and submit a schedule for completion of groundwater assessment and an updated PAR. On 8 February 2002, Regional Board staff received and approved with modifications the Workplan for Additional Groundwater Assessment, which included the GW-1 well abandonment and the installation of two additional monitoring wells, MW-2 and MW-3. On 7 June 2002, site closure was again requested in the Additional Site Investigation and Monitoring Well Abandonment. In a letter dated 30 July 2002,Regional Board staff denied the closure request due to groundwater detections of cis-1,2-dichloroethene(c12DCE)concentrations up to 13 gg/L,which exceeded Water Quality Objectives(MCLS=6 gg/L). Regional Board staff also requested a minimum of four consecutive quarterly sampling events to determine predominant groundwater flow direction, extent of contamination, contaminant trends and seasonal fluctuations in the monitoring wells. Silgan conducted the four consecutive quarters of groundwater monitoring, and requested site closure in the 30 July 2003 Groundwater Sampling&Site Closure Report(2nd Quarter, 4l"of 4 Quarterly Events). Results for all quarterly monitoring events are included in Table 4. In addition to cl2DCE, very low concentrations of Methyl tert-Butyl Ether(MtBE, 1.5 gg/L)were detected in groundwater in April and June of 2003. Prior to 2003, MtBE has not been analyzed at the site. In a letter response dated 26 September 2003, Regional Board staff requested an updated sensitive receptor survey, an estimate of remaining mass of c 12DCE and a fate &transport model to provide estimates of the time needed for groundwater to reach Water Quality Objectives and the distance that the groundwater plume could travel. The 31 October 2003 Update On Closure Request Items For Silgan Container Corporation (Report) included the updated sensitive receptor survey,which revealed one offsite fire protection well located approximately 600 feet northwest of the UST area, and two private water supply wells 1,300 feet and 2,600 feet to the southeast. The Report included a USEPA BIOCHLOR fate and transport model for the remaining c1,2DCE (Enclosure), which predicts a maximum groundwater plume travel distance from 40 to200 feet,with a time to reach Water Quality Objectives varying from 4 to 20 years. Silgan estimates that 0.60 pounds of cl2DCE remain in groundwater. Graphed concentrations of c 12DCE versus time in monitoring wells MW-1 and MW-2 (Enclosure) show a trend of declining concentrations. In a letter dated 4 November 2003,Regional Board staff requested a workplan for monitoring well destruction, stating that No Further Action was required for site cleanup. A Well Abandonment workplan was received on 21 November, and approved in a Regional Board letter dated 24 November 2003. On 22 December 2003, California Environmental Protection Agency 0a Recycled Paper