One of the main concerns with vaping is the use of flavoring agents, especially those containing diacetyl, a chemical known for causing bronchiolitis obliterans, or "popcorn lung." Heating of liquid nicotine in E Cigarettes and Vape Pens Tobacco Prevention Toolkit Stanford Medicine Also known as vapes, e cigarettes may seem safe to use, but they are not. Bilal Bangash, MD, of @BayhealthDE, shares more about vaping. https: t.co 3jlcfw542g (via @AmerMedicalAssn) Will Vaping Lead Teens to Smoking Cigarettes? Johns Hopkins Medicine