The U.S. Department of Energy reported Friday a tank storing radioactive waste at Washington's Hanford nuclear reservation is leaking between 150 to 300 gallons per year.
The news raises concerns about the integrity of similar tanks at Hanford and puts added pressure on the federal government to resolve construction problems with the plant being built to alleviate environmental and safety risks from the waste.
According to the DOE, the leaking tank was built in the 1940's and was stabilized in February 1995, when all pumpable liquids were removed by agreement with the State.
The DOE said in a statement the tank contains 447,000 gallons of sludge, a mixture of solids and liquids with a mud-like consistency. It's the first tank which has been documented to be losing liquids since interim stabilization was completed in 2005.
Governor Jay Inslee said there is "no immediate public health risk," and the newly discovered leak may not reach the groundwater for years.
Inslee also said the the tank is one of the farthest from the Columbia River.
"I am alarmed and deeply concerned by this news," Inslee said. "This was a problem we thought was under control, years ago, when the liquids were pumped from the tanks and the sludge was stabilized. We can't just leave 149 single-shell tanks with high-level radioactive liquid and sludge sitting in the ground, for decades after their design life. Let me be clear: Washington State has a zero tolerance policy on radioactive leakage. We will not tolerate any leaks of this material to the environment."
DOE reports there are 177 tanks at the Hanford site, 149 of which are single shell tanks including the leaking tank.
The tanks, which are already long past their intended 20-year life span, hold millions of gallons of a highly radioactive stew left from decades of plutonium production for nuclear weapons.
"I am alarmed about this on many levels," Inslee said at a news conference. "This raises concerns, not only about the existing leak ... but also concerning the integrity of the other single shell tanks of this age."
Inslee said the state was assured years ago that such problems had been dealt with and he warned that spending cuts - particularly due to a budget fight in Congress - would create further risks at Hanford. Inslee said the cleanup must be a priority for the federal government.
"We are willing to exercise our rights using the legal system at the appropriate time. That should be clear," Inslee said.
Inslee said the state has a good partner in Energy Secretary Steven Chu but that he's concerned about whether Congress is committed to clean up the highly contaminated site.
Inslee said he plans to meet with Chu next week to discuss clean up options.
The Associated Press contributed to this report