Hazardous chemicals discovered in flavored e cigarette vapor E Liquid Ingredients] What Is Vape Juice Made Of? Grey Haze UK It's time to clear the air about vaping. It's not just water vapor and it's definitely not safer than smoking. Swipe to get the facts, not just the hype. 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.