The Department of Energy announced Thursday new evidence of more leaking waste from the oldest of Hanford's double-shell tanks. (Photo courtesy of KNDU-TV-DOE).

While DOE has known for about a year that Tank AY-102 was leaking, this new discovery has prompted officials to pressure the federal agency about what they are going to do about the waste.

The discovery of dry evidence of a leak was found in a new area, away from previous leaks. Measuring about 7 feet long, and almost two feet wide, the waste shows no signs of being "wet," and monitoring officials say there's no evidence any waste or water made it's way into the soil below the tank. It's between the two walls of the double-shell container.

This is the third discovery of a leak in AY-102, which is the oldest of the 28 double-shell tanks built at Hanford. They were constructed beginning in 1968 to allow waste from the older 149 single-shell tanks to be pumped out. The old tanks had begun leaking, some of them breaking down from the heat generated by the waste.

The Washington State Department of Ecology has been urging DOE to empty that tank to minimize leaks, and has pressured the federal government for not taking more action since the leaks were first discovered over a year ago.