Rear Adm. Ronny Jackson, President Trump’s pick to lead the Veterans Affairs Department, has been accused of creating a hostile work environment, drinking while on duty and improperly prescribing drugs to staff during his time as White House doctor to two administrations, according to Montana Sen. Jon Tester.

Tester, the top Democrat on the Senate Veterans’ Affairs Committee, detailed the allegations Tuesday in an interview with NPR’s All Things Considered.

“All I can tell you is we didn’t initiate this discussion,” Tester told host Ari Shapiro. “This discussion came when we were notified by folks who work with Adm. Jackson, folks in the military.”

Montana Sen. Jon Tester Weighs In On Delayed Confirmation Hearing For Ronny Jackson

Tester said more than 20 military employees disclosed the as-yet-unsubstantiated allegations to senators ahead of a hearing to debate his nomination to lead the VA. That hearing was indefinitely postponed to allow further investigation by the committee.