Top 7 moments from RFK Jr.'s contentious Capitol Hill hearing

6. Firing of CDC Director Susan Monarez

During his exchange with Sanders, Kennedy also defended his recent removal of CDC Director Susan Monarez less than a month after she was confirmed.

Accusing Monarez of lying in a recent Wall Street Journal op-ed, in which she claimed she was fired for refusing to "pre-approve" and rubber-stamp CDC panel recommendations without adequate scientific review, Kennedy claimed Monarez herself told him that she is untrustworthy.

"I told her that she had to resign because I asked her, 'Are you a trustworthy person?' And she said, 'No.' So if you had an employee who told you they were not trustworthy, would you ask them to resign, senator?" Kennedy said.

Lawyers for Monarez pushed back against Kennedy's assertions, which they dismissed as "patently ridiculous," according to Politico.

"Dr. Monarez stands by what she said in her op-ed in The Wall Street Journal, would repeat it all under oath and continues to support the vision she outlined at her confirmation hearing that science will control her decisions," Mark S. Zaid and Abbe David Lowell said.