RALEIGH — North Carolina’s environmental and health agencies last year agreed that neighbors of a Duke Energy coal ash pit shouldn’t drink their well water for their own health — a decision Gov. Pat McCrory’s appointees reversed in March, a state toxicologist testified in a sworn statement Duke’s lawyers on Tuesday asked a judge to bury.

“I think the primary reason for my disagreement with (the reversal) is that, number one, we had already gone through an extensive months-long vetting process to reach consensus … between the two departments on how to protect these folks in these areas,” toxicologist Kenneth Rudo said earlier this month. “And decisions had been made at the top of both departments as of last year to tell these folks that had levels that were agreed upon by both departments for hexavalent chromium, to not drink their water.”

Duke Energy Corp. lawyers on Tuesday asked a federal judge to block the public release of Rudo’s partial deposition. They argued his words may be inadmissible in court and could prejudice a jury in the looming lawsuit over whether pollutants are seeping from coal ash pits at Duke’s Buck power plant near Salisbury into groundwater in violation of federal law.

In April 2015, North Carolina officials issued letters to the owners of 330 water wells near Duke Energy’s coal-burning plants that their well water was too contaminated with the heavy metals vanadium and hexavalent chromium to use. Both can occur naturally in soil or as a result of industrial byproducts like coal ash, the waste after coal is burned to generate electricity.

Some wells showed hexavalent chromium levels many times higher than the state’s warning level — a one-in-a-million risk for a person to develop cancer over their lifetime, according to state officials.

But a risk reassessment led to a decision that the earlier warnings were based on a standard much stricter than nearly anyplace else in the country, state health director Dr. Randall Williams said. In March, the state Department of Health and Human Services reversed its earlier warning — telling homeowners who draw from 235 of the wells that their water is “as safe to drink as water in most cities and towns across the state and country.”

What the new letters didn’t say is that there are no federal standards for vanadium or hexavalent chromium that municipal water systems must meet, environmentalists said.

Rudo’s deposition should be kept private because it is incomplete, Duke Energy lawyers argued in court papers. Attorneys for the country’s largest electric company had little opportunity to question him on July 11 and a follow-up deposition hasn’t been set, they said.

“With hours of questions still to be asked, lawyers are just beginning to challenge Dr. Rudo’s motives, his claims and his credibility,” Duke Energy spokeswoman Paige Sheehan wrote in an email.

Lawyers from the Southern Environmental Law Center, who are suing Duke Energy in the case, are responsible for a “reckless campaign to create fear and confusion around coal ash by cherry picking court documents in order to manipulate the media and the public,” Sheehan wrote.

SELC lawyers have released earlier depositions of state employees involved in the conflicting advice over to neighbors of coal ash pits. SELC wanted to do the same with Rudo’s testimony, which is why Duke Energy lawyers asked a judge to stop them.

“We believe the public has a right to know how its state government has handled this important issue of drinking water supplies and public health,” SELC senior attorney Frank Holleman said.

Emery P. Dalesio

Associated Press