Andrew Wheeler during his confirmation hearing to be Deputy Administrator of the Environmental Protection Agency before the United States Senate Committee on the Environment and Public Works on Capitol Hill in Washington, D.C. on November 8th, 2017. Alex Edelman/CNP/DPA/AP
Washington CNN  — 

A former coal lobbyist will be the new acting head of the Environmental Protection Agency after former agency Administrator Scott Pruitt resigned on Thursday.

Andrew Wheeler was confirmed by the Senate in April to be the EPA’s deputy administrator, but he was criticized by Democrats for his past ties to energy lobbyists.

Wheeler worked at FaegreBD Consulting and Faegre Baker Daniels law firm before going to the EPA.

His firm’s clients included Murray Energy, which calls itself “the largest coal mining company in America.”

Prior to his time lobbying, Wheeler served on Capitol Hill as a Republican staff member for the Senate Environment and Public Works Committee and as a top aide to Sen. Jim Inhofe, an Oklahoma Republican who’s an outspoken climate change skeptic.

Wheeler is originally from Hamilton, Ohio, his biography on the EPA website said. He has a law degree from Washington University in St. Louis and an MBA from George Mason University.

His appointment to a government position has come with lots of criticism from Democrats.

CNN previously reported that Senate Minority Leader Chuck Schumer dubbed Wheeler “a former industry lobbyist who has worked on behalf of big polluters and climate change deniers.”

“He has spent years working to undermine or lobby against the environmental protections he may soon oversee,” the New York Democrat said at the time of Wheeler’s confirmation hearing.

Pruitt, whose tenure as head of the organization was plagued by numerous scandals, officially stepped down from his role Thursday, according to a tweet from President Donald Trump. The move left Wheeler to assume his duties.

“Now we have his deputy administrator coming in, and it’s not clear whether this person is committed to protecting the environment. That’s the real problem,” Sen. Ben Cardin, D-Maryland, said Thursday.

CNN’s Daniella Diaz and Ted Barrett contributed to this report.