Friday, the U.S. Department of Energy released information indicating one of the single-shell tanks at Hanford from 1945 is leaking.

Monitoring has shown over the last year levels in tank SST T111 have been dropping -- this indicates a leak. It is one of the single-shell tanks built during World War II to hold radioactive waste generated from the Manhattan Project. As far back as 1979, the tank was labled an assumed leaker, meaning it was likely to start oozing chemicals soon.

In 1995, some interim stabilization was completed, and whatever could be pumped out of the tank was removed. One of 177 tanks at Hanford, it contains over 447,000 gallons of a mud-like collection of sludge and solids. Leakage from the tank ranges anywhere from 150 to 300 gallons a year.

However, no significant changes in the levels of radiation or other chemicals in the area have been detected. From the DOE Press Release:

Monitoring wells in the T Tank Farm, where Tank T-111 is located, have not identified significant changes in concentrations of chemicals or radionuclides in the soil. DOE is continuing to monitor its network of monitoring wells in the area of T Tank Farm and is evaluating possible next steps.

Governor Jay Inslee issued a press release on the matter after being notified of the leak from Energy Secretary Chu:

I am alarmed and deeply concerned by this news. 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 siting 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.

Fortunately, there is no immediate public health risk. The newly discovered leak may not hit the groundwater for many years, and we have a groundwater treatment system in place that provides a last defense for the river. However, the fact that this tank is one of the farthest from the river is not an excuse for delay. It is a call to act now.

I am appreciative of Secretary Chu’s personal attention to this matter, and know he will deploy all technically-possible solutions to address the leaking tank. I will meet with the Secretary next week in DC, to hear about the Department’s progress on stopping the leak and preventing any further tank leaks at Hanford.

Federal officials have not specified what the next steps will be.