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fi Soil Gas Investigation Work Plan Raymond Investment Corporation May 24,2006 Page 3 Based on historic groundwater monitoring data for the Site through the third quarter of 2005, Condor recommended consideration for Site closure in the Third Quarter Groundwater Monitoring Report, dated October 5, 2005. In a telephone conversation on October 27, 2005, Ms. Victoria McCartney of the SJCEHD indicated that she would review the Site for potential closure and requested that groundwater monitoring continue while the potential for-closure was evaluated. In a letter dated February 22, 2006 Ms. McCartney indicated that a recommendation for Site closure could not yet be supported because the SJCEHD did not believe that the vertical extent of impacted soil . and groundwater had been .demonstrated in the area of soil borings S133 and S134 (advanced in May 2004) and that further groundwater and soil investigation were necessary to assess the lateral extent of hydrocarbon..contamination in the area of f anal down-gradient of S133. Ms. McCartney added that additional monitoring wells were required to assess the lateral extent of groundwater contamination and requested submittal of a work plan by April 10, 2006.In addition, Ms. McCartney requested submittal of a sensitive receptor survey (SRS) report and a work plan to evaluate the threat of vapor intrusion inside �. the Site buildings by May 1, 2006. At Condor's request, Ms. McCartney approved an extension of the submittal deadline for the additional soil and groundwater investigation work plan to May 31, 2006 and the SRS report and vapor intrusion evaluation work plan to June 30, 2006, in her Ietter dated April 7, 2006. On March 9, 2006, the average groundwater elevation in the monitoring wells was -17.4 feet; the t estimated groundwater.gradient for the Site was 0.006 ft/ft to the east-northeast. Monitoring wells MW-i and MW-2 were sampled (in the above referenced letter dated February 22, 2006, Ms. McCartney ' reduced the groundwater monitoring requirements for MW-3 from quarterly to annually) and none of the analytical constituents were detected at or above the laboratory,reported detection limits in either of the samples. 3.0 FIELD AND ANALYTICAL METHODS This section includes a description of proposed health and safety procedures,proposed.soil gas sampling procedures, and laboratory analyses. 3.1 HEALTH AND SAFETY REQUIREMENTS Prior to initiating fieldwork at the Site,:all field personnel will familiarize themselves with the Site- Specific Health and Safety Plan (HASP). The HASP pertains to field activities and includes information on potential hazards expected to be encountered at the Site,personal protective equipment, and directions to and telephone numbers for the nearest hospital. A copy of the HASP is included in Appendix B. All personnel working at the Site will .have completed 40 hours of classroom training and 24 hours of supervised field training concerning hazards that may be encountered at hazardous waste sites. 3.2 SAMPLING PLAN The soil gas sampling plan described in this section is based on information contained in the Advisory— Active Soil Gas Investigations, previously mentioned in Section 1.0. Proposed soil boring locations are shown in Figure 3,Appendix A. 3.2.1 Number,Type, and Analyses of Samples Three soil borings near the building will each be installed approximately five feet from the building and sampled at depths of 6, 11, and 16 feet below ground surface (bgs). The proposed sampling depths are i i A � fiala CONDOR