A Kernel of Truth: Diacetyl, Popcorn Lung and E Liquids Dinner Lady 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 Did you know some flavored vapes contain diacetyl, a chemical linked to popcorn lunga rare, irreversible lung disease? It scars the small airways, making it hard to breathe. Symptoms can mimic Is There Diacetyl In E liquid? Vaped