A US teenager was recently reported to have developed the oddly named medical condition "popcorn lung" after vaping in secret for three years. Officially known as bronchiolitis obliterans , popcorn lung is a rare but serious and irreversible disease that damages the tiny airways in the lungs, leading to persistent coughing, wheezing, fatigue and breathlessness.
Authors
- Donal O'Shea
Professor of Chemistry, RCSI University of Medicine and Health Sciences
- Gerry McElvaney
Professor of Medicine, RCSI University of Medicine and Health Sciences
The term "popcorn lung" dates back to the early 2000s when several workers at a microwave popcorn factory developed lung problems after inhaling a chemical called diacetyl - the same ingredient used to give popcorn its rich, buttery taste.
Diacetyl, or 2,3-butanedione, is a flavouring agent that becomes a toxic inhalant when aerosolised. It causes inflammation and scarring in the bronchioles (the smallest branches of the lungs), making it increasingly difficult for air to move through. The result: permanent, often disabling lung damage.
While diacetyl is the most infamous cause, popcorn lung can also be triggered by inhaling other toxic chemicals, including volatile carbonyls like formaldehyde and acetaldehyde - both of which have also been detected in e-cigarette vapours.
The scariest part? There's no cure for popcorn lung. Once the lungs are damaged, treatment is limited to managing symptoms. This can include bronchodilators, steroids, and in extreme cases, lung transplantation . For this reason, prevention - not treatment - is the best and only defence.
And yet, for young vapers, prevention isn't so straightforward.
The vaping trap
Vaping is especially popular among teenagers and young adults , possibly due to the thousands of flavoured vape products available - from bubblegum to cotton candy to mango ice. But those fruity, candy-like flavours come with a chemical cost.
E-liquids may contain nicotine, but they also include a chemical cocktail designed to appeal to users. Many of these flavouring agents are approved for use in food. That doesn't mean they're safe to inhale.
Here's why that matters: when chemicals are eaten, they go through the digestive system and are processed by the liver before entering the bloodstream. That journey reduces their potential harm. But when chemicals are inhaled , they bypass this filtration system entirely. They go straight into the lungs - and from there, directly into the bloodstream, reaching vital organs like the heart and brain within seconds.
That's what made the original popcorn factory cases so tragic. Eating butter-flavoured popcorn? Totally fine . Breathing in the buttery chemical? Devastating.
Vaping's chemical complexity
With vaping, the situation is even murkier. Experts estimate there are over 180 different flavouring agents used in e-cigarette products today. When heated, many of these chemicals break down into new compounds - some of which have never been tested for inhalation safety. That's a major concern.
Diacetyl, though removed from some vape products, is still found in others. And its substitutes - acetoin and 2,3-pentanedione - may be just as harmful . Even if diacetyl isn't the sole culprit, cumulative exposure to multiple chemicals and their byproducts could increase the risk of popcorn lung and other respiratory conditions.
This was tragically echoed in the story of the American teen who developed the disease. Her case is reminiscent of the 2019 Evali crisis (e-cigarette or vaping product use-associated lung injury), which saw 68 deaths and over 2,800 hospitalisations in the US. That outbreak was eventually linked to vitamin E acetate - a thickening agent in some cannabis vape products. When heated, it produces a highly toxic gas called ketene.
More recent studies are raising alarm bells about vaping's impact on young people's respiratory health. A multi-national study found that adolescents who vape report significantly more respiratory symptoms, even when adjusting for smoking status. Certain flavour types, nicotine salts, and frequency of use were all linked to these symptoms.
So, what does this all mean?
It's clear that history is repeating itself. Just as workplace safety rules were overhauled to protect popcorn factory workers, we now need similar regulatory urgency for the vaping industry - especially when it comes to protecting the next generation.
Learning from the past, protecting the future
Popcorn and vaping might seem worlds apart, but they're connected by a common thread: exposure to inhaled chemicals that were never meant for the lungs. The danger lies not in what these chemicals are when eaten, but in what they become when heated and inhaled.
If we apply the lessons from industrial safety to today's vaping habits - particularly among young people - we could avoid repeating the same mistakes. Regulations, clear labelling, stricter ingredient testing, and educational campaigns can help minimise the risks.
Until then, stories like that of the American teen serve as powerful reminders that vaping, despite its fruity flavours and sleek designs, is not without consequence. Sometimes, what seems harmless can leave damage that lasts a lifetime.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
