Why Do Disposable Vapes Make You Feel Sick? Causes and Solutions Can Expired Vape Juice Kill You? [Shocking Facts] Grey Haze UK 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 An Ohio woman says her vape habit landed her in a medically induced coma after doctors had to suction two liters of black and bloody fluid from her damaged lungs. Read the