RALEIGH, N.C. (AP) — North Carolina Gov. Pat McCrory’s administration on Tuesday again lashed out against a state toxicologist who said in sworn testimony he worried that state officials cleared well water near Duke Energy coal ash pits as safe to drink despite a chemical known to cause cancer.

High-ranking officials of the state’s environmental and health agencies sought to isolate state toxicologist Ken Rudo as the creator of a too-severe standard for the presence of hexavalent chromium in groundwater. The standard — a one chance in a million that people drinking contaminated water could develop cancer over a lifetime — was set by the state agencies before warning letters were issued last year to about 330 neighbors of Duke Energy coal sites.

Rudo produced “questionable and inconsistent scientific conclusions,” the statement by state public health director Dr. Randall Williams and Department of Environmental Quality Assistant Secretary Tom Reeder said. The statement was issued a week after Rudo’s deposition in a lawsuit against Duke Energy was obtained by The Associated Press.

Rudo testified in the deposition that his office was pressured by McCrory administration officials to add misleading and confusing language to the 2015 warning letters. Rudo said he refused to sign the letters because he was concerned they played down the public health risk.

In March, Williams and Reeder told well owners that standard was set too high and that their water is as safe as most municipal supplies. That put the state’s view in line with Duke Energy in saying the previous standard was too cautious.

Williams “knowingly told people that their water was safe when we knew it wasn’t,” said Rudo, who has been the state’s toxicologist for nearly 30 years.

Rudo described in his deposition that federal drinking water standards for drinking water cover municipal drinking water supplies, not well water. There is no current well water standard for hexavalent chromium. The warnings to well owners were required under state law once testing had shown the wells to be contaminated at what state officials concluded were unsafe levels of hexavalent chromium, Rudo testified.

“For Chromium 6, Rudo’s analysis is out of step with the federal government and 49 other states. If one followed the threshold he proposes, every state would have to issue ‘do not drink’ orders to tens of millions of people,” the statement by Williams and Reeder said.

Requests to interview Williams and Reeder about their statement were not answered Tuesday. Rudo did not respond to a request for comment.

The third-largest spill of toxic coal ash in U.S. history from a Duke Energy coal pit in 2014 led to the state law that launched groundwater testing around all 14 of the company’s North Carolina coal-burning plants. Coal ash is the byproduct of burning coal to generate electricity.

Duke Energy denies its coal ash pits are the source of the contamination, noting hexavalent chromium occurs naturally as well as in industrial byproducts like coal ash.

McCrory’s chief of staff last week accused Rudo of lying in his deposition when he said the governor, who worked for Duke Energy for nearly three decades prior to his election, was briefly on the phone during a meeting at which Rudo was quizzed on why it was necessary to warn the residents.

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