The state Department of Environmental Resources said video taken inside the 36-inch-wide concrete pipe shows wide gaps between seams through which potentially contaminated water is gushing in from the dump above.
"We're concerned about the leaks we see in the 36-inch pipe and want to prevent a second pipe failure," said Tracy Davis, director of the state Division of Energy, Mineral and Land Resources.
The agency didn't provide an estimate for how much liquid from the dump is currently spilling into the river. Officials have given Duke 10 days to come up with a plan to fix the leaks.
A state inspector received the video from Duke during a visit to the site Tuesday. Company officials had indicated no serious problems with the second pipe, but when the inspector viewed the video Thursday he observed "infiltration ... dripping and flowing" through leaky joints. At three different points, the inspector described what he termed as a "gusher."
Word of the new problem comes after the Waterkeeper Alliance identified seepage Thursday coming from yet another pipe at the site, five days after Duke claimed the contamination was contained. The environmental group said its test of the wastewater flowing into the river detected arsenic levels 18 times the standard for human exposure.
Federal prosecutors on Monday served Duke and state officials with grand jury subpoenas demanding records as part of a federal investigation into the Feb. 2 spill, which contaminated the river so badly the state has advised against prolonged contact with the water or eating fish.
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