Maggie Davis cannot remember a time when her mother, Mary Kerrie, didn't smoke.

Davis, of Blairsville, Georgia, said her mother gravitated toward e-cigarettes about a decade ago, as a way to quit traditional tobacco. She assumed they were healthier.

On Sept. 6, Mary Kerrie Davis, 52, died suddenly.

Davis' father called her with the crushing news.

"The first thing I said was, 'You have to get this investigated,'" Davis told NBC News.

"I'm never smoking again"

Davis, 21, said her mother usually smoked e-cigarettes with nicotine, but started using THC cartridges about a year ago.

Because THC is illegal in Georgia, Davis said her mother turned to the black market.

This past July, Mary Kerrie traveled from her Georgia home to California and vaped legal marijuana, according to Davis.

When Mary Kerrie returned home, she developed a ragged cough, and was initially diagnosed with pneumonia.

Davis wrote about her mother's illness, death and the ensuing investigation in a poignant essay published by her college's newspaper, the Pepperdine University Graphic.

"My mother groaned between coughs, 'I'm never smoking again; I'm throwing out all of my e-cigarettes and weed pens,'" she wrote.

"My father, a doctor who is all too familiar with the dangers of vaping, responded to her declaration of quitting by saying, 'Good, Mary. There are some things that are precious, like your vision and your breath, and you just can’t hurt those things.'"

"'Breath is precious,' my mom repeated."

Davis said she texted her mom, telling her she hoped it wasn't the "vaping disease" that was going around. At that time, news of the mysterious illnesses had started to circulate nationwide.

Two days later, Mary Kerrie was dead.

"It was devastating," Davis said. "Over and over again, all I could say was, 'why MY mom?'"

It's torn my family apart. It took my mom away from me.

Despite an ongoing national investigation of vaping-related illnesses and deaths, Davis told NBC News that it was difficult at first to convince health officials to look for a link between Mary Kerrie's vaping history and her death.

An autopsy and other tests have since been completed, with results pending.

The Georgia Department of Health has reported one death from vaping-related lung illness, but it's believed to be of a different person.

Davis is convinced vaping is to blame for her mother's death.

"It's torn my family apart," she said. "It took my mom away from me."

Maggie Davis, seen here as a baby, says vaping is to blame for her mother's death at age 52. Courtesy Maggie Davis

She said writing the essay for her college paper has been therapeutic in the weeks since her mother's death.

"My mother had declared she was done with vaping, yet her decision came too late," Davis wrote. "She will never see her youngest daughter graduate high school, nor her oldest graduate college. She will never see her daughters married or meet her grandchildren."

"Her absence, a sudden and jarring hole in my family, will be felt for decades to come."

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