Stephen Hahn, nominee to be commissioner of the Food and Drug Administration, testifies during his confirmation hearing in the Senate Health, Education, Labor and Pensions Committee on Wednesday, Nov. 20, 2019.

President Donald Trump's nominee to run the Food and Drug Administration was grilled at his Senate confirmation hearing Wednesday about he would tackle the teen vaping epidemic.

Dr. Stephen Hahn was pressed at the Senate Health, Education, Labor and Pensions Committee hearing.

Facing new data showing more than one-quarter of high school students vape, the Trump administration in September announced it was readying a ban on all flavors of e-cigarettes except tobacco. Trump has since appeared to have backed off the plan amid pressure from conservatives and the vaping community, drawing sharp criticism from Democrats and public health advocates.

Sen. Patty Murray, D-Wash., and ranking member of the committee, said Trump's backtracking shows he's "more swayed by the tobacco industry and politics than by children's health."

"We need an FDA commissioner who will push back hard to put children's health first," Murray said.

She challenged Hahn on whether he was committed to finalizing a ban on flavored e-cigarettes. Hahn touted his experience as a lung cancer doctor, saying he has seen the "ravages" of tobacco firsthand. He said "aggressive action" is needed to prevent another generation of Americans becoming addicted to nicotine, but he stopped short of committing to pushing the president to ban flavors.

"I understand the final compliance is under consideration by the administration," Hahn said. "I look forward to their decision. I am not privy to those decision making processes, but I very much am in support of aggressive action to protect our children."

Hahn said he has not had a conversation with Trump about the flavor ban. In an exchange with Sen. Mitt Romney, R-Utah, Hahn said he does not want to "prejudge" the policy because he does not have "all the facts they might have."

"I can tell you this, for sure, sir, I will use science and data to guide the decisions if I'm fortunate enough to be confirmed, and I won't back away from that," Hahn said.

Hahn is an oncologist and chief medical executive at Texas' MD Anderson Cancer Center. The Senate HELP committee is tentatively planning to vote on Hahn's nomination on Dec. 3. If approved, his nomination will be sent to the full Senate for a vote.