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Rivers swollen by Hurricane Florence continue to rise across North and South Carolina. Just one reason that's a problem - there are pits filled with toxic coal ash right by some of these rivers. Pits at two locations have already been flooded. A third site in Conway, S.C., is now at risk. NPR's Nurith Aizenman reports.
UNIDENTIFIED PERSON #1: Hey guys, welcome. You guys don't mind putting your equipment down so we can put on...
NURITH AIZENMAN, BYLINE: I'm meeting up with a team of environmentalists on a motorboat.
UNIDENTIFIED PERSON #1: Yes.
UNIDENTIFIED PERSON #2: Life jackets?
UNIDENTIFIED PERSON #1: Yeah, you definitely need to have - you have to put on life jackets.
AIZENMAN: We're on what looks like the edge of a lake, but it's actually a parking lot that's been flooded by the Waccamaw River. We push off. Our guide is Cara Schildtknecht with the group Waterkeeper Alliance.
CARA SCHILDTKNECHT: And right here, we're about to turn down what would normally be Elm Street.
AIZENMAN: You can just see the street sign peeking above the water. We pull alongside the bank of the river, where through some trees I can just make out an enormous pond.
SCHILDTKNECHT: Now, this is the coal ash pond that contains 200,000 tons of coal ash.
AIZENMAN: The worry - as the water keeps rising, it will flood the pond.
SCHILDTKNECHT: And so that coal ash could potentially enter the river.
AIZENMAN: The ash is waste that was dumped here by a coal-burning power plant that operated on this land from the 1960s to 2012. Back on land, I talk to Donna Lisenby, Waterkeeper Alliance's expert on coal ash.
DONNA LISENBY: I've been working on coal ash issues in North Carolina and around the world for 10 years now.
AIZENMAN: She says power plants have created more than a thousand dumps like this across the country. And this ash is chock-full of heavy metals.
LISENBY: Arsenic, cadmium, chromium, lead, mercury, selenium, thalium.
AIZENMAN: When those get into the river, they kill off fish and other wildlife. And they can also get into drinking water. The floodwaters from Hurricane Florence have already caused coal ash to spill into river water from two other sites just across the border in North Carolina. That's kept Lisenby busy collecting water samples.
LISENBY: I have deployed to disaster site after disaster site. I've gotten four hours' sleep on average.
AIZENMAN: The most serious spill so far has been at a plant an hour and a half away. It's called the L.V. Sutton plant near Wilmington, N.C., operated by the power company Duke Energy. At least 1,500 cubic meters of ash poured into the adjacent Cape Fear River.
LISENBY: Let me see if I can pull up pictures on my phone.
AIZENMAN: In the photos, the water is just choked with gray ash. Duke Energy says it has tested the waterways and found that the ash spill has not affected overall water quality. But tests by state officials are still pending, and Lisenby says she won't be convinced until she gets results back from the sample she collected herself. Over the years, Duke Energy has been the subject of federal charges and settlements over illegal dumping and major spills.
LISENBY: Our experience with Duke Energy is that they don't find what they don't look for.
AIZENMAN: Lisenby has got better things to say about the South Carolina power company Santee Cooper. They had actually been in the process of cleaning up this coal ash dump on the Waccamaw River.
LISENBY: And they would have had this last ash pond cleaned up if we had not gotten this storm.
AIZENMAN: Her takeaway - regulators need to insist that power companies clean up these dumps a lot faster. She thinks climate change has made this problem urgent.
LISENBY: It's never been more dangerous for our rivers and our communities than it is today because of superstorms that are much larger, much stronger and dump much more water into these ash ponds.
AIZENMAN: A spokesperson for Santee Cooper said the company has been using helicopters to drop in bags of rocks to shore up the ash pond. They're still hopeful they can prevent the kind of overflow that happened in North Carolina. As for Lisenby, all day, she says, she's been leading her colleagues in a chant.
LISENBY: Say it again three times fast.
DONNA LISENBY AND UNIDENTIFIED COLLEAGUES: Lord willing and the river don't rise.
AIZENMAN: Nurith Aizenman, NPR News, Conway, S.C.
POST-BROADCAST CLARIFICATION: In an earlier introduction to this report, it was not made clear that there are multiple coal ash pits at two flooded locations in South Carolina. Transcript provided by NPR, Copyright NPR.