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The geologist will obtain soil from the base of the piping trenches in areas as directed by San Joaquin County Health (20-foot intervals of the piping runs and from beneath each dispenser). The geologist will then screen the entire excavation with the PID, placing samples from the areas of highest responses into a ziplock bag and sealing the bag. The bag will be allowed to warm in the sun. An alternative warming method, using automobile engine heat, may be used in cloudy or foggy weather to heat the soil thereby releasing vapors into the headspace of the sealed baggy. The geologist will then peal the seal of the baggy just enough to introduce the sample port of the PID into the bag to obtain a reading of the vapors inside the bag. If the readings are in excess of 50 ppmv (parts per million vapor) a decision will be made to excavate that area. Some high readings are the result of water vapor entering the detector and can result in false positives (false high values). OVER-EXCAVATION If an area is over-excavated, the PID will be used to screen the soils being excavated to determine when enough soil has been removed and to monitor the ambient air near the excavation as part of the Health and Safety Plan. It is anticipated that no more than 400 cubic yards of gasoline contaminated soil will be generated during the over-excavation process. Over-excavation will not exceed 15 feet below ground surface. And will not extend more than three feet laterally from the original piping/dispenser excavation sidewalls. Pre-approval from the UST State Fund will be secured prior to over-excavation as suggested by Mr. Mike Infurna, San Joaquin County Health Underground Storage Tank Program. EXCAVATED SOIL HANDLING All excavated soils will be placed on the stations asphalt surface and covered with a plastic liner. Samples of the excavated soil will be obtained after completion of the excavating. Once laboratory results have been received (approximately five working days) the soils will be profiled into an accepted landfill. It is anticipated that the soil will be non-hazardous and non-hazardous manifest transported for disposal to Forward Landfill, Stockton, California. The frequency of sampling will adhere to Forward Landfill and San Joaquin County Health requirements. TANK FUND COST BENEFIT— PREAPPROVAL Prestige Oil has contracted W. A. Craig, Inc. to perform the piping/dispenser upgrade. Wickland will use W. A. Craig, Inc. for any necessary over-excavation, see Appendix A for rates and material costs. W. A. Craig, Inc. pricing is within the published Underground Storage Tank Cleanup Fund Cost Guidelines noted under SB 2004. W. A. Craig, Inc. will bill Wickland direct, no markup. Mobilization will not be charged to the over-excavation since the equipment will already be on site for the piping/dispenser removal/upgrade. 3 R-603 piping upgrade 1-2000