Popcorn Lung: The Deadly Secret in Your Vape! Did you know that the sweet, tempting flavor in your e liquid could be hiding a chemical called Diacetyl? This chemical, which tastes Vaping, Diacetyl, and Popcorn Lung: Is the Threat Real? What is Popcorn Lung? Popcorn Lung is a serious, permanent lung disease caused by inhaling harmful chemicals like diacetyl, sometimes found in flavored vapes. Tips for Parents & Caregivers: Talk Risk assessment of inhaled diacetyl from electronic cigarette use among teens and adults ScienceDirect