And the 18-year-old reality star recently added fuel to the fire with a new Snapchat video of her smoking from what resembled a vape.
Caitlyn Jenner's daughter flaunted her ability to blow O-rings from her E-cigarette while sitting in the passenger seat with BFF Jordyn Woods.
The clip was uploaded on fan account kylizzlesnapchats including footage of Woods driving and recording videos at the same time.
Use of e-cigarettes reached an all-time high among the middle school and high school student demographics, peaking at 2 million teens, according to the Centers for Disease Control and Prevention.
"We want parents to know that nicotine is dangerous for kids at any age, whether it's an e-cigarette, hookah, cigarette or cigar," said CDC director Dr. Tom Frieden in a statement. "Adolescence is a critical time for brain development. Nicotine exposure at a young age may cause lasting harm to brain development, promote addiction and lead to sustained tobacco use."
Hawaii became the first state to raise the smoking age to 21 effective Jan. 1.