A second leak of suspected radioactive material at the Hanford Nuclear Reservation was recently detected, the U.S. Department of Energy confirmed Friday.
As with the first leak revealed last month, the new material was found in a gap between the walls of a double-walled storage tank (see photos in gallery).
The leak was found during a routine inspection and was described as a three-foot mass that tested positive for high-level radioactivity.
The second mass has not been measured or tested yet. Officials with the federal Office of River Protection said no radioactive material has escaped the outer wall of the tank and that there is no danger to the public or Hanford workers
The discoveries raise questions about the integrity of the double-walled tanks. Reactors at Hanford manufactured plutonium for the U.S. nuclear arsenal starting in World War II. Closed in 1987, the 586 square mile reservation is home to 177 underground tanks holding chemical and nuclear waste.
Washington state is threatening legal action if the federal government doesn't respond to questions about cleanup delays at the nation's most contaminated nuclear site.
The legal threats are the latest volley in a long-running dispute between the state and federal government over cleaning up decades of pollution left from nuclear weapons production at south-central Washington's Hanford nuclear reservation.
The biggest questions center on construction of a massive waste treatment plant to convert highly radioactive waste into a stable, glass form. The $12.3 billion project has encountered numerous technical problems and delays in the past decade and costs for the project have skyrocketed.
Most recently, the Energy Department said it may not be able to meet the 2022 operating deadline established under a court-ordered consent decree when Washington last sued over missed deadlines. In June, the agency also said a new cost and schedule for the project would be delayed at least a year.
In a letter to Energy Secretary Stephen Chu released Thursday, Washington Gov. Chris Gregoire and state Attorney General Rob McKenna gave the agency until Sept. 26 to respond to their questions about the delays or face returning to court.
The two sides signed the consent decree in October 2010. Just 13 months later in November 2011, the Energy Department informed the state that some deadlines were at risk, the letter said. Six more months passed before additional details were provided.
"We are writing to ask for your commitment to respond with reasonable diligence to the circumstances you believe have put the Consent Decree schedule at risk, including taking all reasonable steps to avoid or minimize any possible delays from the current schedule," the letter said.
The federal government created Hanford in the 1940s as part of the top-secret project to build the atomic bomb. Today, it is the nation's most contaminated nuclear site, with cleanup expected to last decades.
The cornerstone of that cleanup has long been considered the so-called vitrification plant, which will convert millions of gallons of radioactive waste into glasslike logs for permanent disposal. The highly toxic stew -- enough to fill dozens of Olympic-size swimming pools -- has been stored in aging, underground tanks, some of which have leaked, threatening the groundwater and neighboring Columbia River.
Additional reporting from the Associated Press.