Acetoin is a precursor to diacetyl in e cigarette liquids ScienceDirect Popcorn Lung & Vaping: The Dangers Of Diacetyl Explained worried about the Popcorn Lung diacetyl rumour (please read) Vaping Forum Planet of the Vapes Yes, vaping is toxic. A U.S. teen developed "popcorn lung" after secretly vaping for three years a permanent, life altering disease. Officially known as bronchiolitis obliterans, the condition scars the lungs' tiniest