One of the most serious risks of vaping? A condition called popcorn lung, or bronchiolitis obliterans. It's rare, but when it hits, it's permanentscarring the smallest airways in the lungs and causing E Cigarette Use, Small Airway Fibrosis, and Constrictive Bronchiolitis NEJM Evidence Popcorn lung: What is it, and who is at risk? Harvard Health Teenager Diagnosed Of 'Popcorn Lung'; Doctors Suspect Vaping Habit CodeBlue