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ATC SITE SAFETY PLAN <br /> FACILITY BACKGROUND <br /> In March 1998, during construction activities associated with the extension of D'Arcy <br /> Parkway, a suspected surface spill was discovered and construction activities were <br /> suspended. A soil sample was collected which indicated the presence of total petroleum <br /> hydrocarbons as diesel (TPHd). On March 25, 1998, ATC Associates was retained to <br /> investigate the extent of the suspected surface spill. Five test pits were excavated the <br /> vicinity of the suspected spill. No evidence of petroleum hydrocarbons was noted in the <br /> first four test pits to depths of approximately 12 feet below ground surface (bgs) and the <br /> pits were backfilled. Petroleum hydrocarbons were detected in the fifth test pit starting at <br /> a depth of approximately four feet bgs. Soil was excavated laterally and to a depth of <br /> approximately 14 feet bgs, the estimated depth to groundwater. ATC collected <br /> confirmation samples from the excavation sidewalls and bottom. A grab sample was <br /> collected from the groundwater as it entered the excavation. Excavated soil was stockpiled <br /> on visquene plastic on site. <br /> Laboratory analysis of soil samples from the first four test pits and the sidewalls of the <br /> excavation indicated nondetectable to low TPHd concentrations. TPHd was detected in the <br /> bottom soil samples at concentrations of 290 ppm and 340 ppm and low levels of MTBE, <br /> benzene, ethyl benzene, and xylenes were also detected. TPHd, MTBE, and xylenes were <br /> detected in the grab groundwater sample at concentrations of 190,000 parts per billion <br /> (ppb), 150 ppb, and 300 ppb, respectively. <br /> WORK PLAN <br /> Task One: <br /> Supervise the installation of a minimum of four soil borings to depths of <br /> approximately 14 feet. At least one soil sample and one groundwater sample will be <br /> collected from each boring from areas which exhibit physical indications of <br /> contamination. Excavate impacted soil laterally and extract one to two saturated <br /> volumes of groundwater from the pit for off-site disposal. Collect confirmation soil <br /> and groundwater samples. Samples will be analyzed for BTEX (EPA Method 8020), <br /> TPHd and TPHg (EPA Method 8015 Modified), and MTBE (EPA Method 8020). <br /> PAGE 4 <br />