Robert F. Kennedy Jr. returns to Capitol Hill on Thursday for a second confirmation hearing to become the country's next Health and Human Services secretary.

He will appear before the Senate Health, Education, Labor and Pensions Committee, following a contentious hearing Wednesday before the Senate Finance Committee. 

Kennedy will be questioned by senators who have worked in the health field such as Sen. Bill Cassidy, R-La., who is also a physician. 

The hearing will begin at 10 am EST. 

Long an advocate for reform to American federal health programs and a critic of chemical additives in food, Kennedy's nomination has roiled lawmakers, some of whom have called him anti-vaccine.

During the first hearing, Kennedy was asked about his previous comments where he opposed childhood vaccines. 

Independent Vermont Sen. Bernie Sanders referenced infant onesies with anti-vaccine slogans sold by a company founded by Kennedy. 

"You're coming before this committee and you say you're pro-vaccine, and yet your organization is making money selling a child's product for to parents for $26 which casts fundamental doubt on the usefulness of vaccines," Sanders said to Kennedy. 

Kennedy had said at the start of the hearing that he was pro-vaccine and all his kids were vaccinated. 

Other Trump nominees that have hearings Thursday include Kash Patel for FBI director and Tulsi Gabbard for director of national intelligence.