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 Popcorn lung: What is it, and who is at risk? Harvard Health Experts show that flavored e cigarettes cause irreversible lung damage. A U.S. teen developed "popcorn lung" after secretly vaping for 3 years a permanent, life altering disease. Officially known as bronchiolitis obliterans, the Health officials investigating dangers of vaping, verifying danger