"Your job is not to bring down a huge compliance and enforcement penalty" on someone who violates environmental rules, Reeder said. "Your job is to help him get back into compliance."

Reeder said the agency had a "moral obligation" to review environmental regulations and "relieve the regulated community of that burden."

North Carolina Gov. Pat McCrory, who worked for Duke Energy for 28 years, has declined to say whether the state intends to fine or sanction Duke. State regulators have also sidestepped the issue, saying they are focusing on the spill.

Duke Energy donated at least $1.1 million to McCrory and his supporters during his 2012 campaign, according to campaign finance reports cited by the Associated Press. The utility has also donated millions to Democrats.

Both Duke Energy and the state say their tests show that levels of heavy metals are within state safety standards. The state said Sunday that arsenic levels had dropped to within safe standards since samples taken Feb. 3 — a day after the spill was reported — showed levels higher than allowed by law. Reeder said a state report that the early arsenic levels were safe was "an honest mistake."

Holleman said state regulators did not tell his group about Monday's request to delay the settlement, even though the environmental center is a party to the state lawsuits.

"We're the citizens who reported the crime," Holleman said. "They are the law enforcement agency, yet they work out a deal with the lawbreaker. Meanwhile, the Dan River is running full of coal ash."

Municipal water authorities in Danville, Va., the downstream city closest to the spill, have said that normal filtering procedures have made water drawn from the Dan River safe to drink.

Waterkeeper Alliance, an environmental group, has used kayaks to take water samples at the spill site; state regulators and Duke have taken samples at least two miles downriver, where the coal ash is diluted as heavy metals sink into sediment at the river bottom.

Waterkeeper and another environmental group, Appalachian Voices, said they found levels of arsenic, lead, chromium and other heavy metals far above state and federal safety standards that would leave the river polluted for years to come.