Authorities say wastewater sludge from a wastewater treatment plant was intentionally dumped into Shoe Heel Creek in Scotland County, and criminal charges may result.

"What we have found is an illegal discharge of solid, or sludge," said Belinda Henson, surface water protection supervisor in the state Division of Water Quality’s Fayetteville office.

Environment officials said the sludge came from the wastewater treatment plant run by the Laurinburg-Maxton Airport Commission. They said they believe the superintendent had been dumping sludge it into the creek since at least November.

“It's the worst I've seen in my career here," Henson said.

Sludge is the material left over from wastewater treatment, such as fertilizer. Henson said sludge could kill fish, though scientists have not found any evidence of that in Shoe Heel, a lowland creek naturally darkened by decaying vegetation.

It is unclear how much sludge wound up in the Shoe Heel watershed, but investigators said it was a substantial amount. WRAL asked for access to the dump site, but the director of the airport commission said 'not a chance.'"

Gary Arnett, who retired from the commission last month, is accused of dumping the sludge. He reportedly told investigators that he was trying to save money.

"The lawyer said not to say anything,” Arnett said. Asked about the theory that dumping was a way to save money by not having the sludge hauled away, Arnett said, “I can't say anything, bud. I mean, I did say that part, but that's all I can say."

Authorities said they believe Arnett acted alone and was not told to dump the waste.

"We don't see this very often, believe it or not. not to this extent. So it's new to us," Henson said.

Investigators said the sludge has not affected any drinking water sources, and they are still assessing the environmental impact.

The State Bureau of Investigation and the U.S. Environmental Protection Agency are investigating whether there were violations of the federal Clean Water Act.