On Sunday, May 29th, EPA was notified that a tank had been overturned in an attempt to move it from one property to another. The tank had an estimated capacity of 300 gallons and was believed to contain 100 - 200 gallons of unknown petroleum at the time of the spill. The oil released to the soil and entered a storm drain approximately 10 yards away, which empties to 10 Mile Creek, a tributary to the Boise River. Attempts to have the responsible party hire a qualified contractor failed and the State of Idaho requested EPA's assistance in conducting the cleanup. EPA OSC Barber and START contractor arrived on scene on Monday, May 30th, assessed the discharge, and began cleanup.
On Tuesday, 5/31/05, EPA ERRS subcontractor Environmental Management Solutions (EMS) completed hand excavation of contaminated soils between tank spill and storm drain, as well as excavation of contaminated soils on south side of Victory Road, in driveway where leaking tank was deposited. EMS arranged for vacuum truck to remove remaining petroleum from the tank. Also removed contaminated soils, where accessible, between rock riprap at storm drain outfall. Removed contaminated vegetation and debris at spill site and downstream, including a large accumulation of contaminated debris at an obstruction approximately 15 yards downstream from the storm drain outfall. Cleaned out contaminated storm drain segment using absorbent pads and a long pole. Replaced absorbent boom and pads around storm drain outfall, and installed absorbent boom at two nearby downstream locations.
On Wednesday 6/1/05, EMS backfilled and compacted excavated areas on both sides of Victory Road. Also removed from site for temporary storage at their warehouse (pending analytical results for disposal) remaining 55-gallon drums of contaminated soils, and contaminated vegetation and debris wrapped in vizqueen. Volume of material removed is twenty-eight 55-gallon drums of contaminated soils and approximately 2 cubic yards of removed contaminated vegetation and debris. EMS and START contractor demobilized.
Since 6/1/05, EMS has been checking the site every other day, and after significant storm events, to monitor absorbent boom and pads around storm drain outfall and downstream, and change out pads as necessary.
Small amounts of sheen continues to emanate from among the rock riprap at the storm drain outfall, particularly after flushing events from heavy rainfall. It was impossible to remove the riprap and cleanup pockets of trapped petroleum among the rocks, without possibly compromising the integrity of the road bed and bridge across 10-Mile Creek. The fuel that is continuing to escape from the rocks is being adequately contained by the arrangement of absorbent pads and boom around the site. EMS will continue to monitor every other day and change out sorbents as necessary so long as significant sheen is emanating from the area, or until the OSC determines such activity is no longer necessary.
Upon receipt of analytical results for disposal, EMS will properly dispose of removed soil and debris that is currently in temporary storage at their warehouse.
Even though the material in the tank was by appearances and odor probably old diesel fuel, the OSC determined that analysis was necessary for proper disposal since there was no available history of the tank use or contents. Analytical results for priority metals and pesticides/herbicides is pending. If analytical results were to show that the petroleum was contaminated with significant concentrations of hazardous substances, funding for this action may need to be switched to CERCLA.
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