A 17-year-old diagnosed with “popcorn lung” after three years of vaping highlights the irreversible dangers of the habit.

Professor Donal O’Shea from RCSI University explains that the condition, formally known as bronchiolitis obliterans, is linked to diacetyl—a chemical used in vape flavourings and once found in microwave popcorn factories. When aerosolised, diacetyl becomes toxic, causing permanent scarring in the lungs’ smallest airways.

There is no cure; treatment only manages symptoms with bronchodilators, steroids, or, in severe cases, lung transplants. Prevention, O’Shea stresses, is the only real protection.

While banned in the UK and EU, diacetyl still appears in illegal and international vape products. Other harmful substances like formaldehyde and acetaldehyde also pose risks. With over 180 flavouring agents in use—many untested for inhalation—the cumulative exposure to chemicals increases the danger. O’Shea concludes that avoiding vaping altogether is the only safe option.