President Trump’s nominee to head the Environmental Protection Agency’s watchdog office moved closer to confirmation Wednesday with approval from a Senate panel, raising questions about what might happen to the acting inspector general’s investigation into agency chief of staff Ryan Jackson.

Sean O’Donnell, Trump’s nominee to be the EPA’s new inspector general, advanced from the Senate Environment and Public Works Committee through a unanimous voice vote. Top senators on the panel said speeding his full confirmation could help resolve mounting tensions over Jackson's actions.

O’Donnell’s nomination has been met with relatively little controversy. Senators in both parties have praised his qualifications, which most recently include serving as a trial attorney in the Department of Justice’s criminal division.

O’Donnell is an “exceptional candidate” and has the “right experience to fill the void,” Chairman John Barrasso, a Wyoming Republican, said during a Wednesday business meeting.

But if confirmed by the full chamber, O’Donnell could be joining an office embroiled in a battle with top Trump EPA officials.

Acting EPA Inspector General Charles Sheehan has accused Jackson, the EPA’s chief of staff, of “open defiance” in two probes the office is conducting, at least one of which dates back to former EPA Administrator Scott Pruitt’s tumultuous tenure. Sheehan has also criticized EPA General Counsel Matt Leopold for essentially giving agency staff “free rein” to flout inspector general requests for information.

Tom Carper of Delaware, the top Democrat on the committee, said the dispute “illustrates the importance of the role that Mr. O’Donnell is seeking to perform.” Carper added, though, that he hopes the fight between the EPA acting inspector general and political officials “will be resolved to everyone’s satisfaction” before O’Donnell’s confirmation vote before the full Senate.

Barrasso told reporters following the committee’s vote that he hopes to get O’Donnell’s nomination approved by the full Senate before the end of the year.

He said having a Senate-confirmed inspector general could help smooth over tensions, but he didn’t say how, beyond noting he thinks “it’s just better to have confirmed people making these recommendations.”

Barrasso also said he has reviewed the details of the dispute between the acting inspector general and Jackson and said he has “full confidence” in Jackson.

At the root of the dispute is the inspector general office’s allegation that Jackson is refusing to reveal how he received testimony from an independent EPA science adviser ahead of a 2017 congressional hearing. Democrats in Congress have accused Jackson of attempting to influence that testimony, which focused, in part, on the Trump administration’s policy limiting which types of scientists could serve on the EPA’s advisory boards.

EPA political officials, though, have defended Jackson, arguing the chief of staff has attempted to set up meetings recently with the inspector general to no avail.

O’Donnell, in his confirmation hearing, did pledge to “doggedly” investigate any abuses or ethics violations of EPA officials, including those who have left the agency. But he hasn’t said specifically how he would handle the investigation into Jackson.