Doctors are warning about a rare but serious lung condition linked to vaping, known as popcorn lung (bronchiolitis obliterans). The disease causes permanent scarring in the lungs' smallest airways, leading to ongoing While vaping is not risk free, it is less harmful than tobacco Our World in Data Community Request Diacetyl Center for Research on Ingredient Safety Experts warn that flavored e cigarettes can cause irreversible lung damage, as seen in a U.S. teenager who developed "popcorn lung"a severe and permanent condition called bronchiolitis obliteransafter secretly vaping for three years.