RICHLAND, Wash. -- The U.S. Department of Energy says just one of the older single-walled storage tanks at the Hanford Nuclear Reservation appears to be actively leaking.
The agency recently examined 20 tanks that showed decreased liquid levels and confirmed that only one was actively leaking.
The underground tanks contain radioactive wastes left over from the production of plutonium for nuclear weapons.
The Energy Department said Wednesday that the one tank that is leaking, known as T-111, appears to be stabilizing.
The agency says evaporation accounts for the loss of fluid in some tanks.
As many as 67 tanks are suspected of having leaked in the past. But leaking was believed to end when most liquids were removed from the single-walled tanks in 2004.