A bluff collapsed next to a coal power plant in Wisconsin on Monday, sending debris, dredging equipment and a pickup truck into the lake. No one was hurt in what the Coast Guard says was a "freak accident."
"It is probable that some of the material that washed into the lake is coal ash," a company spokesman says.
The Milwaukee Journal Sentinel reports the EPA is revamping regulations around coal ash following a pond washout in Tennessee in 2008 that created an environmental disaster.
Coal ash can be nasty stuff, according to a report in Scientific American. The magazine notes "the waste produced by coal plants is actually more radioactive than that generated by their nuclear counterparts."