CHARLOTTE, N.C. (AP) -- An environmental group is threatening to sue to stop coal ash from a Duke Energy Carolinas plant from polluting a source of Charlotte's drinking water.
The Southern Environmental Law Center said Tuesday that it's sending Duke a notice that it will file a lawsuit under the federal Clean Water Act.
At issue is the Riverbend power plant. The environmental group says Duke has been storing coal ash in lagoons leaking waste into the Catawba River.
The group says it's representing the Catawba Riverkeeper Foundation, which is monitoring the site.
Duke spokeswoman Erin Culbert says the company is reviewing the filing. She says Duke has been monitoring water quality at the site for decades. She says the water quality is good and that drinking water supplies are safe.