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Remedial Excavation During Construction

Los Angeles Orthopedic Hospital

During grading operations an unknown UST was discovered at a construction site at the former location of a portion of the Los Angeles Orthopedic Hospital. FREY was retained by the developer to collect soil samples from beneath the UST upon its removal and to assess the extent of concentrations of petroleum hydrocarbons in soil beneath the UST. The UST was observed to be in a degraded condition showing moderate signs of corrosion. It was unknown at the time of its removal what the UST had been used for prior to its discovery at the Site.

Laboratory analysis of soil samples collected during excavation activities classified the petroleum hydrocarbons to be consistent with a heavy fuel oil historically used for heating purposes. Soil was observed to be saturated with heavy oil during excavation activities. Laboratory analysis of soil samples collected from beneath the UST detected total petroleum hydrocarbons (carbon range C6 to C36) (TPH) at concentrations ranging from 11,000 to 22,000 mg/kg.

FREY conducted over-excavation activities in 2011 to excavate the majority of the mass of TPH. The excavation was measured to be approximately 16,000 square feet (approximately 160 feet by 100 feet) with depths ranging from 12 to 30 feet below ground surface. A total of 10,129.25 tons of soil with elevated concentrations of petroleum hydrocarbons was excavated and transported to Soil Safe, Inc. located in Adelanto, California, for treatment and recycling.

FREY performed confirmation soil sampling at the direction of the Los Angeles City Fire Department (LACFD) upon completion of soil excavation activities. A total of 47 soil samples were collected from the walls and bottom of the excavation. Concentrations of TPH in soil were detected at levels below the local oversight limits. FREY removed the source of the petroleum hydrocarbons (The former fuel UST), assessed the extent of petroleum hydrocarbons in soil, and successfully conducted remedial action resulting in the removal of a total of approximately 10,129.25 tons of petroleum hydrocarbon impacted soil from the Site. The case was granted closure by the Los Angeles City Fire Department in January of 2012.

Environmental Remediation Services

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