SPOKANE, Wash. (AP) — Workers on the Hanford Nuclear Reservation in Washington state have finished cleaning up one of the nation's most contaminated radioactive waste sites, the U.S. Department of Energy said Thursday.
The dangerous wastes at the site known as the 618-10 Burial Ground stem from the production of plutonium for nuclear weapons and took eight years to clean up, the agency said.
"I'm proud of the workers for safely completing this very complex and high-hazard work," said Doug Shoop, manager of the DOE Richland Operations Office.
The 580-square-mile site Hanford site is located in southeast Washington state.
During the cleanup, workers retrieved more than 2,200 55-gallon drums, plus other waste, some of it buried more than 20 feet underground.
In total, workers removed more than 512,000 tons of contaminated soil and waste debris, which was taken to Hanford's hazardous-waste landfill.
The 7.5-acre burial ground contained highly radioactive waste from Hanford laboratories and fuel development facilities in the 1950s and 1960s. Poor record-keeping at the time meant many of the waste types were unknown, the department said.
The work started in 2009.
Democratic U.S. Sens. Patty Murray and Maria Cantwell, along with U.S. Rep. Dan Newhouse, hailed Thursday's milestone.
"I applaud the thousands of men and women who show up to Hanford every day and who made this milestone possible," Murray said.
The area will be graded to a natural contour and native vegetation will be planted next year to help restore the site to a natural state, the agency said.
Hanford was created by the Manhattan Project during World War II as the nation raced to create an atomic bomb. It produced most of the plutonium for the nation's nuclear arsenal during the Cold War and contains the nation's largest volume of nuclear waste.
The cleanup work costs more than $2 billion per year and is expected to take decades. The lawmakers said they will press the federal government to continue funding the work.
Progress is being made.
The Energy Department recently announced that it was essentially finished removing radioactive wastes from 16 of Hanford's 177 underground storage tanks.