Updated

Duke Energy says a second pipe under a coal ash dump in North Carolina is not in immediate danger of collapse, despite concerns from state regulators that the pipe could fail and trigger another toxic spill into the Dan River.

The state Department of Environmental Resources said Friday that video taken inside the concrete pipe shows wide gaps through which potentially contaminated water could gush and then flow into the river.

Duke spokeswoman Paige Sheehan says the company's assessment is that "no immediate action" is necessary. The state has given Duke 10 days to come up with a plan to fix the leaks.

The third largest coal ash spill in U.S. history was triggered Feb. 2 when a similar pipe at Duke's dump collapsed, turning the river gray for miles.