Nuclear-weapons and energy production have left a legacy of radioactive waste at 131 sites across the U.S. The top five that require remediation:HANFORD, WASH.

More than 45 years of producing plutonium for nuclear bombs left 53 million gallons of radioactive waste, much of it stored in leaky tanks.SAVANNAH RIVER SITE, S.C.

This 310-square-mile facility produced plutonium and tritium for nuclear bombs and is now home to 38 million gallons of radioactive waste.OAK RIDGE RESERVATION, TENN.

The national lab here was a research facility for nuclear reactors and weapons production. The legacy: 350 areas contaminated with radioactive waste.IDAHO NATIONAL ENGINEERING AND ENVIRONMENTAL LAB

Once home to 52 nuclear reactors, the INEEL ended up with a stockpile of nuclear waste that's the size of a football field and 335 feet deep.ROCKY FLATS ENVIRONMENTAL TECHNOLOGY SITE, COLO.

After nearly 40 years of producing nuclear weapons, this site was left with 100 tons of radioactive residue, including 3 tons of plutonium.