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RESPONSE TO COMMENT 8: Contaminated soil in the pit at Location 2 will be assessed in the SAWP to evaluate the need for removal of contaminated soil. The extent of this soil removal will be outlined in a site remediation work plan to be developed in the future based on findings of the SAWP. COMMENT 9: As the depth of original soil samples obtained were between 15 and 20 feet, the recommended soil borings shall be advanced to maximum depth of 40 feet or until ground water is encountered. RESPONSE TO COMMENT 9: The rationale for proposed boring depths for each tank location is discussed below. Former tank and proposed boring locations are shown on Plates 2 through 4 of the SAWP. Location 1: The soil samples analyzed during the removal of the 500 gallon tank at Location 1 (SAWP, Plate 2) were taken at 12 feet as documented by Canome Report Number 85-052-4277. The laboratory results are tabularized in the Canonie report as #5 and indicate BTX, PCB, and purgeable halocarbons were nondetect. Total extractable petroleum hydrocarbons were detected at 26 mg/kg. The Kleinfelder SAWP proposes sampling to a 20-foot depth to evaluate the extent of contamination if present. Field testing for total hydrocarbon compounds using a Foxboro flame ionization detector (FID) is proposed screen samples chosen for analysis. One sample from the highest FID reading and from the bottom of each boring will be submitted to lab analysis. Results from FID and visual observation are proposed as rationale for extending borings deeper or to groundwater if warranted. Since the previous lab results during tank removal indicated BTX, PCB, and purgeable halocarbons were non-detect and total extractable petroleum hydrocarbons were detected at only 26 mg/kg, sampling to a 40 foot depth seems unwarranted at this time unless field observations indicate leakage beyond the 20-foot depth. A typical "rule of thumb" used by many agencies to determine if remediation should be undertaken is a concentration of 100 mg/kg or greater of TPH. Therefore, Kleinfelder feels that extending borings to 40 feet is not necessary at this time unless field observation shows presence of contamination at 20 feet. Location 2: Soil borings for this former tank location will be advanced to a minimum of 40 feet or until groundwater is encountered due to the TPH concentrations at 16 feet. COMMENT 10: Describe the extraction tube illustrated on Detail 2 of the above referenced work plan. 192-89-1077 4 KLEINFELDER 9795 Business Park Drive, Suite C, Sacramento, CA 95827 (916) 366-1701