But already, a new fight is brewing, acting EPA Administrator Andrew Wheeler was a coal lobbyist with close ties to the energy industry who has repeatedly slammed climate change. Announcing the resignation, United States President Donald Trumpwrote on Twitter on Friday, "Within the agency, Scott has done an outstanding job, and I will always be thankful to him for this".
Under Andrew Wheeler, the EPA is unlikely to change course. Wheeler's record as a coal lobbyist has drawn immediate scrutiny - as has concerns about his record on ethics.
He was also an aide to Sen. Jim Inhofe if he decides not to run again in 2020.
"We urge him to immediately commit to undoing the massive damage to EPA's work done under Pruitt's leadership".
The former EPA head reluctantly resigned on Thursday after White House chief of staff John Kelly informed him it was time to leave, two people familiar with the situation toldBloomberg. Pruitt is the seventh person to leave a Cabinet-level post in the Trump administration.
"And I think Scott felt that he was a distraction", Trump added.
"You might see a shift in terms of how I talk about some things", Wheeler told the Journal.
Wednesday night, Pruitt was on the White House lawn, watching fireworks explode over the Washington sky. The reason Pruitt persisted so long is the same reason why his environmentalist foes shouldn't break out the organic Champagne: The administrator was doing exactly what his boss wanted.
Pruitt's resignation follows months during which the EPA administrator has been embroiled in one ethics controversy after the next. "That was the position he was originally interested in". Those groups quickly applauded his departure.
Kieran Suckling, from America's Centre for Biological Diversity, said: "Despite his brief tenure, Pruitt was the worst EPA chief in history".
Many of those scandals led to investigations. "The environment doesn't need deregulation, we need more regulations to protect the environment. this should not be a partisan issue", she said. "We can't afford more pollution and asthma attacks - our children's health and their future depends on it". The Government Accountability Office found that he violated spending laws by installing a $43,000 soundproof phone booth in his office - one of the more than half-dozen federal inquiries launched into his management and expenditures.
He had also ordered his EPA staff to do personal chores for him, picking up dry cleaning and trying to obtain a used Trump hotel mattress for his apartment.
Now, in Wheeler, Murray not only has one of his former lobbyists inside the EPA, he has them running it.
The New York Times reported Thursday that the EPA is poised to propose a comprehensive rollback of regulations that would require large cuts in greenhouse-gas emissions from existing power plants, a huge source of planet-warming emissions.