Washington (CNN) The embattled nominee tapped to lead the Department of Veterans Affairs was known as "the candy man" inside the White House, Sen. Jon Tester said Tuesday, citing reports from individuals who raised concerns about his nomination.

The Montana Democrat told CNN's Anderson Cooper that around 20 people raised concerns to his committee about Rear Adm. Ronny Jackson, and according to those people, Jackson would hand out prescriptions "like candy."

Tester described reports to the Veterans' Affairs Committee that alleged that on overseas trips, Jackson would "go down the aisle way of the airplane and say, 'All right, who wants to go to sleep?' And hand out the prescription drugs like they were candy ... and put them to sleep and then give them the drugs to wake them back up again."

Tester's staff told CNN that Jackson would hand out Ambien and Provigil.

"These are called controlled substances for a reason," Tester said on "Anderson Cooper 360."

Read More