Flavored e cigarettes are not harmless. Doctors are now seeing teens with permanent lung damage from vaping. In the U.S., a teenager developed popcorn lung after vaping in secret for three years. This 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 Vaping: Get the Facts. Protect Your Future Anne Arundel County Health Department Vaping linked to teen's 'popcorn lung' type injury