At the time of his resignation, there were more than a dozen inquiries related to Pruitt's conduct by the EPA's Office of Inspector General, the House Oversight Committee, the Government Accountability Office and other watchdogs.
"Administrator Pruitt always welcomes input from Americans", Lincoln Ferguson, an EPA Spokesman, told ABC News in a statement. In 2015, he joined a multi-state lawsuit against the EPA in an ongoing effort to block the Obama administration's Clean Power Plan, which calls for reducing carbon emissions from the USA power sector 32% below 2005 levels by 2030. He weakened rules that kept polluters in check - many of which are being challenged in court - and tried to jettison others like the Clean Power Plan. The group says it also "helped expose many of his scandals" thanks to Freedom of Information Act requests.
Kieran Suckling, from America's Centre for Biological Diversity, said: "Despite his brief tenure, Pruitt was the worst EPA chief in history".
Many of the EPA regulations that Scott Pruitt scrapped or delayed as EPA administrator had not yet taken effect before his resignation.
Newly named acting EPA chief Andrew Wheeler is expected to stick to the Trump administration's business-friendly regulatory policy, but without the lavish spending and perceived secretive ways of the Pruitt era.
Truly, your confidence in me has blessed me personally and enabled me to advance your agenda beyond what anyone anticipated at the beginning of your Administration. Now he will be at a very high-ranking position at the EPA, where he will be in a position to make lots of decisions that could benefit his former clients. He is a former energy industry lobbyist.
Wheeler told the Washington Examiner earlier this year he was focusing on repairing relationships with EPA career staff who bristled at Pruitt's leadership.
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Before taking the job at the EPA, Wheeler worked as an energy lobbyist on Capitol Hill.
"Hi, I just wanted to urge you to resign because of what you're doing to the environment and our country", she begins addressing Pruitt in the video, before blasting him for not believing in climate change and his unquestionable affinity towards the deregulation of environmental protections. "Americans will not tolerate another EPA administrator whose primary goal is to fight the core mission of the EPA".
Before Wheeler took on the post as Pruitt's second-in-command, he was a principle consultant for FaegreBD Consulting.
Pruitt was having trouble covering expenses for both his home in Oklahoma and in Washington, D.C., and he was eager for his wife to start bringing in income. "There is no appropriate basis for retaining a cabinet secretary who has behaved like Pruitt".
Ken Kimmell, president of the Union of Concerned Scientists, suggests that it's time for the EPA to "clean house". "The independent and experienced leader cared deeply about the future of the agency and restored its effectiveness".
"We deserve to have somebody at the EPA who actually does protect our environment". Some of those omitted meetings included a dinner Pruitt attended at a restaurant within Trump International Hotel with coal executive Joseph Craft as well as meetings with Cardinal George Pell, who weeks later was charged with multiple historical charges of sexual offenses, charges Pell denies.