An environmental group says it's planning to use the federal Clean Water Act to sue Duke Energy over coal ash pollution at three plants along North Carolina rivers.
The Southern Environmental Law Center on Tuesday filed a notice of intent to sue Duke for violations at the company's Cape Fear, Lee and Buck plants.
The state Department of Environment and Natural Resources took enforcement action against those plants last year.
Frank Holleman, the environmental law group's senior attorney, says regulators failed to include many of Duke's violations - and didn't require Duke to clean up those sites.
The Clean Water Act allows citizen groups to file lawsuits over environmental violations, but requires them to give 60-days' notice to state regulators to take enforcement action before the case can proceed.