Acting EPA chief Andrew Wheeler is likely to face tough questions about his work as a coal lobbyist and the actions he’s taken to relax certain environmental restrictions when he appears Wednesday for a Senate confirmation hearing.

Wheeler will testify before the Senate Environment and Public Works Committee beginning at 10 a.m. ET. Watch his remarks in the player above.

Wheeler has been serving as acting EPA head since July, when former top official Scott Pruitt resigned amid mounting investigations into possible ethics violations, including lavish spending on travel and other questionable expenses, including a soundproof booth inside his agency office.

READ MORE: Who is Andrew Wheeler?

Trump and other Republicans have praised Wheeler’s approach to the job, and his work in both the private and public sector (he worked both for the EPA and as a legislative aide). In November, the president said he intended to nominate Wheeler permanently to the position, saying at a White House event that “he’s done a fantastic job and I want to congratulate him.”

Environmentalists and Democrats have been wary of how far Wheeler will go to undo some of the environmental protections put in place by the agency under the Obama administration, along with how Wheeler’s lobbying work could present conflicts of interest, an issue that led to a narrow vote last spring confirming Wheeler as the agency’s deputy administrator.

Trump formally nominated Wheeler as EPA chief last week.

The PBS NewsHour will update this story as it develops.