SITE INFORMATION AND CORRESPONDENCE

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• The tank pit samples TP1-B and TP2-B which were taken from soil immediately adjacent to the gasoline storage tanks showed very low concentrations of hydrocarbons, with one sample reported at 180 parts per million (PPM) and one sample showing non-detect. These soils were excavated and removed. • Side wall sample SW-9 which was taken approximately 4 feet east of the tank location, dropped to a concentration of 100 ppm. These soils were also removed. • Confirmation sample SW-11, which was taken approximately 8 feet east of the storage tanks, showed non-detect for gasoline. In addition, it should be known that the entire soil excavation project was overseen by a representative of San Joaquin County and a registered geologist who visually observed the sidewalls of the pit and took numerous readings With a photo ionization detector (PID) to confirm the completeness of the removal. The data and the observations made at the time of the tank removal strongly suggest that the actual source of the hydrocarbons release was not the tanks themselves, but the piping located at the western end of the northern tank, approximately 45 feet to the west of this sampling point. We believe that the technical data on this point is clear. There is no technical justification for requiring further soil investigation on the "vacant lot." It was both logical and appropriate for San Joaquin County to grant closure for the soil remediation of this site. Regarding the 1990 tank removal project, your understanding of that project is in error. That removal activity dealt only with the removal of the station's 550-gallon waste oil tank which was used specifically for the temporary storage of used automotive drain oil. At the time that tank was removed, approximately 60 cubic yards of soil were overexcavated from the tank pit. Soil samples taken at that time showed concentrations of total hydrocarbons in a range up to 270 ppm. The 1,370 gallons of "free product contaminated groundwater" to which Ms. Deutsch refers, were pumped out during the removal of the gasoline storage tanks. The actual "free product" was more accurately described as a "partial sheen" on the water. Regarding the residual soil concentration left behind in 1990, please note that the entire area was removed during the overexcavation of the main tank pit done in 1992. Thus, the soils characterized by these residual concentrations are no longer on the property. 2. Concernsrelated to groundwater flow direction. Ms Deutsch's concern relates to the possibility that seasonal variation in groundwater flow direction might cause contaminated groundwater, if it were present, to flow in a northeasterly direction beneath the vacant lot.