President Donald Trump’s pick to lead the Department of Veterans Affairs’ confirmation hearing has been delayed as senators probe “hostile work environment” allegations against him, according to several reports.

The ranking Democrat on the Senate Veterans Affairs committee, Sen. John Tester (D-MT) is reviewing allegations against Trump’s nominee, White House physician Admiral Ronny Jackson, according to reports from Politico, CNN, CBS and The Washington Post.

Sources who spoke with CBS said current and former White House medical staffers have accused Jackson of “excessive drinking on the job, improperly dispensing meds.” Tester told CNN that the allegations against Jackson would be troubling “only if true.” Tester has reportedly called for the hearing to be delayed, according to CBS.

The Associated Press and the Post previously reported that senators were mulling delaying Jackson’s confirmation hearing in order to discuss his lack of experience running an agency as large as the VA. The hearing was originally set for Wednesday, but the timing is now uncertain, according to the Post and Politico.

Republicans and Democrats on the committee spoke about the allegations over the weekend and met in person on Monday to discuss whether the accusations would derail Jackson’s nomination, according to Politico. Sen. Tom Tillis (R-NC) told Politico that the discussions were mostly “conversational” and that the hearing may be “pushed back pending a review of some of this stuff that, like I said, I’ve only heard on a conversational basis. I think that’s where we’ll spend our time this week.”

Sen. Richard Blumenthal told several outlets that the allegations will require “very close and careful scrutiny.”

“There’s a need for very exacting and close scrutiny and vetting,” he said. “And some questions that need to be answered. I’m not going to comment on any of the specifics, except to say we’re going to be doing very close and careful scrutiny.”

Trump nominated Jackson to run the VA after he fired former secretary David Shulkin, who was ousted after facing allegations of expensive travel and misconduct by at least one of his staffers.