In early Februry of this year, a drainage pipe underneath a Duke Energy Coal ash pit collapsed.

"We released between 30 and 39 tons of ash into the river," said CEO Lynn J. Good on 60 Minutes.

The unlined pit was used to store coal ash waste from Duke Energy's coal fired Dan River Power Plant, shut down in 2012.

Duke Energy says they've spent twenty million dollars cleaning up the river.

Coal ash contains toxins like arsenic and mercury.

In November of this year, watchdog groups discovered this orange-colored leakage in the Yadkin River.

It was next to coal ash pits at Duke Energy's “buck station”, shut down in 2013.

Frank Holleman, with the Southern Environmental Law Center, who's suing Duke Energy, told CBS News they want ash moved out of unlined pits, and into lined, dry storage, away from waterways.

Duke Energy says it could cost ten billion dollars to move the one hundred million tons of ash in their 32 North Carolina ash pits.

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