The interior wall of a double walled nuclear waste storage tank at Hanford is leaking. KING 5 reported last week the leak was suspected after material was found between the walls of the tank. The Department of Energy (DOE) confirmed the leak on Monday. The announcement emphasizes that the material that escaped from the inner wall is still contained by the exterior wall and there is no risk of public exposure. The discovery is a setback, however, in the transfer of nuclear waste from the older, single shelled tanks to the newer, double shelled tanks. An emergency pumping plan requires the waste be removed the tank quickly, but the DOE said it is still assessing the situation and did not announce its plan for dealing with the substance which has been determined to be highly radioactive. Tank AY-102 contains 850,000 gallons of waste. It is the oldest of the double walled tanks and the first to be identified with a leak. Several of the single walled tanks have already leaked waste into the soil and groundwater.