Understanding Vape Liquids: The Role of Propylene Glycol, Vegetable Glycerin, and Glycerol CIV Plus On Health E cigarettes affect lung biology, even in those who've never smoked Propylene glycol & vegetable glycerin Some reports state that these new, flavored smoking devices are less harmful than tobacco cigarettes but how safe is vaping? In this third part of a four part series, China Daily examines the Propylene hi res stock photography and images Alamy Banned Dangerous Vape Ingredients to Avoid in Your Vape Juice