Propylene Glycol (PG) Antibacterial Activity Infographic Flickr Exploring PG Allergy: Sensitivities, Allergies and What Vapers Can Do About It E Cigarette Direct Vaping propylene glycol and vegetable glycerine may lead to lung inflammation HOW TO TALK TO YOUR KIDS ABOUT VAPING No tobacco product is harmless according to CDC scientific evidence. E cigarette aerosol that users breathe from the device and exhale can contain harmful substances including heavy metals like lead, volatile organic compounds,