U.S. Sen. Michael Bennet, a Colorado Democrat, tore into Robert F. Kennedy Jr., President Donald Trump’s pick to become the nation’s top health official, in a contentious confirmation hearing Wednesday in Washington.

“We are truly through the looking glass this morning here in the U.S. Senate,” said Bennet, who pressed Kennedy on claims made by the nominee over the years about vaccine safety, pesticides and infectious diseases, including COVID-19 and AIDS.

“I hope my colleagues will say to the president, out of 330 million Americans, we can do better than this,” said Bennet, who announced after the Senate Finance Committee hearing that he plans to vote against confirming Kennedy to be Trump’s Secretary of Health and Human Services.

An environmental attorney and a son of the late U.S. attorney general of the same name, Kennedy ran for president last cycle briefly as a Democrat before launching a bid as an independent and later endorsing Trump. He’s seeking to lead a $1.7 trillion agency that will oversee vaccine recommendations, as well as food inspections and health insurance for half the country. Kennedy denies he’s “anti-vaccine.”

Bennet charged that, while Kennedy admitted having vaccinated his own children and required that attendees at a party be vaccinated, he spent years “peddling in half truths, peddling in false statements, peddling in theories that you know create doubt about whether or not things that we know are safe are unsafe.”

Kennedy sought to assure senators that he supports childhood vaccines.

“I believe that vaccines play a critical role in health care,” Kennedy told the committee.

Republicans didn’t ask about Kennedy’s views on vaccines, while Democrats brought up previous remarks that Kennedy has discouraged their use. The accusations often led to terse back-and-forth and outbursts from the audience, including during Bennet’s allotted five-minute questioning.

Democrats also pointed to Kennedy’s writings, podcast appearances and other comments to press their case against Kennedy.

“I just have some — there are many, many things in the record, but I hope that you could answer these questions yes or no,” Bennet said before launching into a rapid-fire series of questions based on previous statements made by Kennedy.

“I’m asking you, yes or no, Mr. Kennedy, did you say that COVID-19 was a genetically engineered bioweapon that targets Black and White people but spared Ashkenazi Jews and Chinese people?” Bennet asked.

Kennedy interjected that he “didn’t say it was deliberately targeted” and had ben quoting from a National Institutes of Health-funded study.

“To move on, did you say that Lyme disease is highly likely a militarily engineered bio weapon? I made sure I put in the ‘highly likely,'” Bennet asked.

“I probably did say that,” Kennedy responded,

Bennet continued, asking whether Kennedy once said “exposure to pesticides causes children to become transgender” and wrote in a book that African AIDS is an entirely different disease from Western AIDS.

Kennedy said Bennet was mischaracterizing what he’d said; Bennet countered he would submit backup for all his questions to the committee chairman.

“Mr. Kennedy, it doesn’t matter what you come here and say that isn’t true,” Bennet concluded. “That’s not reflective of what you really believe, that you haven’t said over decade after decade after decade. Because unlike other jobs we’re confirming around this place, this is a job where it is life and death for the kids that I used to work with in Denver Public Schools and for families all over this country that are suffering.”

Kennedy ended Wednesday’s three-hour hearing with strong endorsements from Republicans for him to lead the department.

But he needs backing from nearly all Senate Republicans to land the job. And one key vote from Republican Sen. Bill Cassidy of Louisiana, a physician who heads up the Health, Education, Labor and Pension committee that Kennedy will sit before Thursday, appeared still uncertain.

Some Republicans said Kennedy emerged unscathed after what they viewed as a pile-on of attacks by Democratic senators. If Democrats vote in a block against Kennedy, he can only lose four Republican votes and still win confirmation.

There had been some opposition to his nomination from conservatives, notably from former Vice President Mike Pence, over Kennedy’s support for abortion rights. Under close watch is Republican Sen. James Lankford, a Republican of Oklahoma who opposes abortion.

He and Kennedy have had “some disagreement on the issue of life,” Lankford said, but Kennedy assured him repeatedly he would follow Trump’s lead on the issue.

Kennedy said he wants to use the National Institutes of Health to conduct more research on food additives, and he would work closely with the U.S. Department of Agriculture to take a look at the federally-funded school lunch program, as well as food assistance for the poor.

Gov. Jared Polis has expressed support for Kennedy’s nomination, saying that he favors a “major shake-up” in institutions like the FDA that have been “barriers to lowering drug costs and promoting healthy food choices.”