In a House Oversight Committee hearing on vaping, Michigan Rep. Rashida Tlaib asked a pro-vaping witness if she is a conspiracy theorist, prompting a tense back-and-forth that ended in the chairman calling for order.

Vicki Porter, a 51-year-old Wisconsin resident, was a witness at the "Don't Vape" hearing invited by the Republican committee members. After she gave testimony about her experience as a former smoker who was only able to quit nicotine after discovering electronic cigarettes.

"It literally changed and probably saved my life," Porter testified. "My lungs are healthy... Vaping is a health miracle to me."

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Tlaib spoke about the history of the tobacco industry and the evolution of the public's knowledge about the dangers of smoking.

"It's so important that you all continue to speak truth about this, because the long-term effects is very dangerous, especially because they have been targeted towards youth," Tlaib said.

The hearing on Tuesday was called in response to the recent Centers for Disease Control and Prevention warning about several deaths linked to vaping, though no specific cause has been identified for lung illnesses thus far.

But things took a turn when Tlaib questioned Porter's motivations for appearing before the committee.

"You know, Ms. Porter, I was reading because I want to know more about you and your beliefs," Tlaib said.

"You call yourself a converted conservative and a reformed Marxist," Tlaib continued. "Are you a conspiracy theorist?"

"I think my politics are entirely irrelevant to this hearing," Porter replied.

"Oh, OK, why were you winking at one of my colleagues on the other side of the aisle? You winked." Tlaib asked.

Porter responded, saying that she knows Wisconsin Rep. Glenn Grothman, who was present at the hearing.

"He's a friend of mine," Porter said.

"I didn't know what the winking was," Tlaib said. "I thought maybe there was something, like a conspiracy thing going on there. I didn't know."

"You think there's a conspiracy in this hearing, ma'am?" Porter said.

The two went back and forth as Tlaib said Porter's idea of "truth" was different from many others at the hearing.

"The truth for me is I quit smoking with e-cigarettes and so did 8 million other people," Porter said as the two talked over each other."

"You're still smoking, ma'am, you're still smoking," Tlaib fired back, referring to the fact that Porter now uses e-cigarettes.

"I'm not smoking," Porter said.

As the chairman called for order, Porter added "And I'm not lying under oath."

More:Trump's proposed ban on vape flavors may not stop teens from vaping, experts warn

The committee's hearing comes as President Donald Trump is considering legislation that would ban the use of flavored e-cigarettes over concern that they are targeted toward children.

According to a new report in Axios, conservative leaders are warning that Trump's proposed ban may hurt his re-election chances in battleground states with significant populations of adults who use vaping products.

The state of Massachusetts has also recently banned sale of all vape products in the state for four months, and the city of San Francisco implemented a ban in June.