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ASPECT CONSULTING <br />PROJECT NO. AS190583A-08  MAY 21, 2025 FINAL 25 <br /> <br />groundwater samples12 for laboratory analysis of gasoline-range TPH/BTEX and diesel- <br />range TPH. In addition, the groundwater sample from the boring located west <br />(downgradient) of the solvent occurrence was analyzed for the full suite of VOCs. The <br />location of the solvent occurrence is identified as hazardous substance location 18 on <br />Figure 2-2. <br />The soil samples and the reconnaissance groundwater samples from the seven borings did <br />not contain detectable concentrations of gasoline-range TPH or BTEX. In addition, no <br />VOCs were detected in the downgradient groundwater sample. The only detectable soil <br />TPH in the eleven soil samples collected was diesel-range TPH (less than 140 mg/kg), in <br />the boring located southwest of the observed release. <br />The 1994 investigation results indicate a highly localized historical release of paint <br />thinner, with no evidence for migration of contaminated groundwater at that time. Further <br />investigation of this area was conducted as part of the RI. <br />3.1.5 UST No. 29 Xylene Release and Independent Cleanup (1989- <br />1994) <br />A release of xylene to soil and groundwater was identified during removal of USTs No. 29 <br />and 67 in 1989 (Landau, 1989). The USTs were positioned end to end and were located <br />immediately west of the Paper Machine Building. UST No. 29 was a 12,500-gallon, <br />single-walled UST used to store xylene, which was used as a solvent for cleaning certain <br />machinery in the paper mill. UST No. 67 was a 12,500-gallon, single-walled UST used to <br />store kerosene (hazardous substance location 22 on Figure 2-2). <br />The xylene release was first identified by solvent odors observed during the initial <br />excavation conducted on November 7, 1989. USTs No. 29 and 67 were subsequently <br />removed on November 8, 1989, and excavated soil was stockpiled on-Site. No release of <br />kerosene was observed during decommissioning of UST 67; however, the xylene release <br />from UST No. 29 was apparent in the UST No. 67 excavation location. During the 1989 <br />UST decommissioning, removal of contaminated soil on the excavation’s north wall was <br />restricted by the tank pad and secondary containment wall for the Pulp Chests located <br />immediately north of the USTs, and currently in place. <br />During the 1989 tank removal activities, a process water drain line was broken and <br />approximately 15,000-gallons of wastewater from the No. 1 and No. 2 paper machines <br />filled the excavation. An oily sheen was observed on the water surface within the <br />excavation. Water sample TS-29 was collected from the excavation for laboratory <br />analysis, and absorbent pads were applied to limit oil material from entering the broken <br />water line. The water line was subsequently repaired on November 9, 1989. After <br />notifying Ecology, approximately 15,000 gallons of water were pumped from the <br />excavation into a Baker tank for temporary storage and subsequent treatment on-Site. <br />Water sample TS-29, collected from the excavation, was submitted for laboratory analysis <br />of TPH and VOCs. A TPH concentration of 310,000 µg/L was detected in the water <br /> <br />12 Grab groundwater samples collected from the soil borings during drilling; no monitoring well was <br />installed.