Environmental Protection Agency Administrator Scott Pruitt has resigned amid accusations of ethics violations while in the position. President Trump accepted his resignation and Pruitt deputy Andrew Wheeler is stepping into the role of acting EPA chief.

In his resignation letter, Pruitt thanked the President for the opportunity but said that “unrelenting attacks on me personally, my family, are unprecedented and have taken a sizable toll on all of us.” On Twitter, the President said that he accepted Pruitt’s resignation and commented that he “has done an outstanding job” during his tenure.

Pruitt represented a significant shift in ideology from the Obama Administration, revisiting previous standards on vehicle emissions and fuel economy and theatened to revoke California's air-quality waiver that allows the nation's most populous state to set its own emissions rules.

Prior to serving as EPA administrator, Pruitt was the Oklahoma Attorney General, where he famously sued the EPA several times. He also played a role in the President’s decision to pull out of the Paris Climate Accord.

In the trucking world, Pruitt proposed an exemption for glider kits that would have allowed the practice to continue and embraced dubious research in favor of that decision, despite protestations by some. He also considered doing away with the EPA’s SmartWay program, a government-industry partnership aimed at reducing emissions and developing fuel saving technologies.

But almost from the beginning of his EPA tenure Pruitt was under fire and, according to the New York Times, was at the time of his resignation the “subject of multiple investigations of ethics and other issues.” These investigations reportedly looked into accusations that Pruittimproperly used his position for favors and misused government funds for personal expenses.

There were indications that the writing was on the wall for Pruitt. In late June, President Trump’s White House press secretary Hogan Gidley acknowledged that the Trump Administration was aware of recent accusations against him and would look into it them.

Related: Clean Vehicle Tech Grows in Face of Shifting Regulations