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 World Lung Day: WAKE UP! DON'T VAPE UP! European Network E Cigarette Use, Small Airway Fibrosis, and Constrictive Bronchiolitis NEJM Evidence Does vaping cause lung cancer? UT MD Anderson