Do you know what you're vaping? Propylene glycol (PG) and vegetable glycerin (VG) are the main liquids in vapes. When heated, these chemicals turn toxic and aren't safe to breathe. Vaping can have serious negative impacts on both your lungs and your overall health. Here are the potential risks that we already know about, even if the vape is nicotine free: The Dangers of Nicotine in Vaping Liquid What Parents Should Know About Vaping Revere Health Vaping Products That Look Like Juice Boxes and Candy Are Target of Crackdown The New York Times