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s. S and JO had a TEH of 24 and 23 r,ig/kg and X% l ec:e of . 13 arid . 11 mg/kg, respectively. The Tri -Regional guidelines use 100 ppm (mg/kg) TPH as a guide- line for estimating need for a clean-up after a spill , but this number is used only as an assessment tool , riot a firm "yes-or-no" answer . The guidlines also state "The level of clean-up is to be determined by assessing the potential impact of residual oil contamination on the groundwater". p„ Resample On August 18, 1989, Sample Locations 8 , 10 and I1 were resampled as close to the original locations as possible. The DH5 was con- tacted to witness the resampling and declined. This time, all three samples showed negative at the detection limits . In as much as excavation had proceeded 5 ' deeper than the deepest contamination detectable by either sight or smelt , it is presumed that the small amount of hydrocarbons found in the original samples were localized trace amounts, either too small to be found or they evaporated between samplings . PARTIAL F I LL I NG OF EXCAVAT I CIV From the time of resampling, August 18, 1989, to the middle of F September, 1989 there was no activity at the excavation. A thor- ough sampling program had been carried out with good results; the pit was refilling with water and vandals, presumeably youths, were entering the fenced area. The plastic covering that had been placed over the spoil piles had blown away owing to the vandals having thrown most of the weights that had been holding the plastic down (automobile tires) into the pit. This can be seen in figures discussed Eater herein. The excavation, with sidewalls of unconsolidated, sandy-silty material , and with water in the bottom, was evidently an atTraction for vandals , and it was a dangerous place for them to be. In addition, the excavation, open into the groundwater table, was a potential contamination entry port ( infiltration gallery) into the groundwater. During early September, 1959, ATO informed Diane Hinson of the potential problem of the open excavation. ]TO decided that they could not wait for the writing of this present document before taking some precautionry action. Therefore. in September,. 1989; all clean soil stored in Pile # 3 (f=igs . 2 "& 3) was returned to — --.-- - ---- _ -__ t-he- e-acauat_ron,=---f-i 1-1-ina i t--to---28 '--to-_--30-'---below---g_.-I . (Fig. -4) , --- { The DHS was informed of this action. 10