Genesee Union Hardware Store Fueling Station, Genesee, ID; Central Environmental Construction for Pacific Northwest Farmer Cooperative
White Shield (WSI) provided site assessment and remediation oversight services at the Genesee Warehouse(now Pacific Northwest Farmer Cooperative) Facility in Genesee, Idaho. Upon lifting one of the gasoline aboveground storage tanks, it was discovered that a hole approximately 2 inches in diameter was present in the bottom of the tank. Following tank removal, WSI began excavating petroleum-contaminated soils from the site. As excavation progressed, it was discovered that the contaminated soils extended to the depth of at least 10 to 14 feet below the former base of the tank and also below the depth that groundwater was encountered, approximately 11 bgs. To facilitate the remediation WSI submitted a plan to the Idaho Department of Environmental Quality requesting approval to dewater the excavation and remove contaminated soils to a depth of 14 bgs. WSI removed approximately 7,000 gallons of water from the excavation and placed it in a former diesel tank for on-site air stripping treatment. Upon completion of the excavation, WSI collected 10 samples from the base of the excavation and 17 samples from the sidewalls to determine if the contaminated soils had been removed. Sample analyses results were used to run the Idaho Risk Evaluation Model (REM) for Risk Based cleanups. The results returned indicated that the site posed a risk greater than is allowed by the State of Idaho Cleanup Regulations. Additional excavation was performed and a total of approximately 7800 cubic yards of soil were removed. Additional samples were then collected from the base and the sidewall of the excavation and were also used in the REM. The results of the REM showed the soil was no longer an exposure pathway of concern. As a result the excavation was backfilled and a plan to install groundwater monitoring wells was submitted to the Idaho Department of Environmental Quality.