Burning coal creates nuclear waste.

Scientific American reports on a series of studies that mess with our sense of common sense. Nuclear power plants should be creating nuclear waste, and coal plants should be creating smog, right? Wrong. Nuclear plants do create nuclear waste, but not nearly as much as coal-burning plants do:

Among the surprising conclusions: the waste produced by coal plants is actually more radioactive than that generated by their nuclear counterparts. In fact, fly ash—a by-product from burning coal for power—contains up to 100 times more radiation than nuclear waste.

At issue is coal’s content of uranium and thorium, both radioactive elements. They occur in such trace amounts in natural, or “whole,” coal that they aren’t a problem. But when coal is burned into fly ash, uranium and thorium are concentrated at up to 10 times their original levels.