Originally Posted by newB

Did you not read the clarification at the bottom?

"As a general clarification, ounce for ounce, coal ash released from a power plant delivers more radiation than nuclear waste shielded via water or dry cask storage."

So, it's not that it is more radioactive, the problem is that it was not being contained. Perhaps they've gotten better at it in the 12 years since the article was written, and 31 years since the source they cited for that statistic.