The emails were provided Thursday to The Associated Press by the Southern Environmental Law Center, which had filed notice in January 2012 of its intent to sue Duke under the Clean Water Act.
Within days, the emails show a Duke lobbyist contacted the N.C. Department of Environment and Natural Resources, where staff exchanged messages discussing "how Duke wants to be sued."
The agency used its authority to intervene in the lawsuit, quickly negotiating a proposed settlement where the $50 billion company would pay a $99,100 fine but be under no requirement to stop its pollution.
Also Thursday, Democrats at the North Carolina legislature said Duke Energy should be forced to move all of its coal ash to lined landfills away from water and make shareholders - not customers - pay for the cleanup.
House and Senate Democrats unveiled Thursday the framework of a bill they intend to introduce when the General Assembly reconvenes in May. They want Republicans in charge of the legislature to join them given last month's coal ash pond rupture along the Dan River.
Rep. Pricey Harrison of Greensboro is the chief author of the proposal, which also would repeal a 2013 provision critics say makes it harder to contain groundwater contamination at a waste dump.
"The House took immediate action designating a team of leaders and experts within the Environmental Review Commission on coal ash to begin working on both short-term fixes and long-term solutions," said Anna Robert, the communications director for North Carolina House Speaker Thom Tillis, in a statement. "Finally, the Democrats are acting on a problem that dates back to numerous Democratic administrations. We look forward to working with the Senate during the short session to eliminate the coal ash threat – at Dan River and the other sites – to North Carolina's waterways."
A statement from President pro tempore of the North Carolina Senate Phil Berger reads, "Sen. Berger is deeply concerned with the recent coal ash spill – that's why he called for the General Assembly's Environmental Review Commission to gather information, assess damage and receive updates on clean-up and prevention efforts to ensure similar events never happen again. He believes fixing these problems should be an important focus of the General Assembly and is confident the information brought forward by federal and state regulators in their ongoing investigations will be helpful in creating a plan."
Other Republican leaders on environmental issues said this week they're collecting more information before deciding the steps to take.
AP reporters Michael Biesecker and Gary D. Robertson contributed to this report