CH2M Hill Plateau Remediation has made a significant dent in work to clean up Hanford's largest waste site.
Workers have hauled about 20,000 truckloads of contaminated soil from 140 acres near a disposal area for radioactively contaminated liquids.
The BC cribs and trenches were built just south of the 200 East Area in central Hanford in 1955. The in-ground disposal system received millions of gallons of waste mostly from a program at U Plant to recover uranium from waste created as irradiated fuel was chemically processed to remove plutonium.
Liquids contaminated with radioactive cesium and strontium were poured into large trenches in the ground, and some of the contaminated soil was spread by the wind from the open trenches.
The waste was salty, which attracted animals, and they spread smaller amounts of the waste through their droppings.
The trenches were covered with sand and gravel in 1969, ending the spread of contamination. But it took federal economic stimulus money to make substantial progress on cleanup of the contamination spread across shrub steppe habitat.
About $34 million of Recovery Act money has been spent on work from fiscal 2009 to 2011 on the 13 square miles near the BC cribs and trenches, called the BC Control Area.
That included the recently completed work to excavate nearly 500,000 tons of contaminated soil, or 20,000 truckloads, in the 140 acres near the cribs and trenches with the most contamination.
"Ecology is pleased to see the completion of the 'core' of the BC Control Area, Hanford's largest waste site by area," said John Price, of the Washington State Department of Ecology, one of the regulators on the project.
The area also includes 2.5 square miles that do not need cleanup and about 1,000 intermittent radioactive "hot spots" elsewhere that will need to be cleaned up.
Contaminated soil in the 140 acres near the trenches was dug up to as much as a couple of feet deep in some places. The soil was hauled to the Environmental Restoration Disposal Facility, a lined landfill in central Hanford for low-level radioactive waste.
"Safety was a high priority on this project," said Al Farabee, Department of Energy project director, in a statement. "Workers moved a tremendous amount of material and in two years didn't have a single injury that was significant enough to record or cause a day away from work."
The soil was hauled using trucks that CH2M Hill calls "super dump trucks" because they carry a larger load than trucks more commonly used at Hanford. That reduced handling by workers and increased the safety margin, according to DOE.
With subcontractors Wildlands Inc. and Ojeda Business Ventures, CH2M Hill has replanted the 140 acres. About 1,000 pounds of seed and 280,000 pounds of mulch were used.