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To avoid cross--contamination, drilling augers were steam-cleaned before drilling each borehole. All soils generated during drilling activities were underlain and covered with 6 ml plastic sheeting. 3.3 Monitoring Well Construction Monitoring Wells MW2, MW3, and MW4 were constructed of 4 inch diameter F480 PVC well screen and casing. A neat cement mixture was used to seal the wells, in accordance with State ' of California Water Well Standards (Dec. 1981, p. 34, para. 4). Well construction details are shown on well/bonng logs (Appendix II). ' Subsequent to installation, the wellheads were surveyed to Mean Sea Level Datum (Table 3) under the direction of a State Certified Engineer. On May 6, 1993, after the wells were allowed ' to stabilize for at least 24 hours, each was monitored for free product in accordance with RESNA's Groundwater Monitoring Protocol The wells were developed and water samples collected after purging a minimum of three well volumes (casing and sandpack). Samples were analyzed by Sequoia Analytical for BTEX and TPHG utilizing EPA Methods 8020 and 8015, respectively. Analytical results for groundwater samples are summanzed in Table 2. Laboratory data sheets and chain of custody documentation are included in Appendix III. Field ' purge logs are included in Appendix IV. 3.4 Subsurface Conditions Soils encountered beneath the site consist primarily of clays and silts with interbedded layers of sand. The maximum depth explored was approximately 91 feet below grade. No soil contamination was detected in any samples collected from the unsaturated zone. Groundwater was encountered at approximately 80 feet below grade and subsequently rose to approximately 74 feet below grade, suggesting that groundwater exists under semi-confined conditions. Based upon the May 6, 1993 monitoring data (Table 3), static groundwater is PAR-093 FML 5 i