The Mysterious Vaping Illness That's 'Becoming an Epidemic' The New York Times Does Vape Juice Expire? Tips to Preserve Your E Liquid Generation V this vape liquid can kill you if you get it on your skin apparently : r mildlyinteresting The Dangers of Nicotine in Vaping Liquid 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.