Health experts are sounding the alarm about a serious condition linked to vaping, known as "popcorn lung" or bronchiolitis obliterans. This irreversible lung disease is caused by harmful chemicals, like diacetyl, found Popcorn lung: What is it, and who is at risk? Harvard Health Flavored e cigarettes are not harmless. Doctors are now seeing teens with permanent lung damage from vaping. In the U.S., a teenager developed popcorn lung after vaping in secret for three years. This Vaping Safety, Smoking, Dangers, Pros, Cons, Debate, E cigarettes, & Tobacco Britannica Popcorn lung: how vaping could scar your lungs for life