An expert has issued a strong warning against vaping, highlighting the risk of developing an irreversible lung condition known as “popcorn lung.”
Though often perceived as a safer alternative to smoking, vaping can lead to severe, permanent lung damage, according to Professor Donal O’Shea, a chemistry expert at RCSI University of Medicine and Health Sciences. His concerns follow the recent diagnosis of a 17-year-old with bronchiolitis obliterans — the official name for the condition behind the nickname “popcorn lung.”
In a compelling piece for The Conversation, Professor O’Shea stresses that prevention is the only true protection against this debilitating disease — and it all boils down to the chemicals being inhaled.
Why “Popcorn Lung” Is a Serious Threat — Not Just a Trendy Term
Despite how it may sound, “popcorn lung” isn’t a social media exaggeration. The name originated from cases among workers at a microwave popcorn factory who developed lung disease after inhaling diacetyl, a flavoring chemical.
“Just like in those factories, flavoured vapes contain diacetyl, which becomes a toxic inhalant when aerosolised,” O’Shea explains.
And it doesn’t take much exposure to cause serious harm.
“It inflames and scars the bronchioles — the smallest airways in the lungs — making it harder and harder to breathe,” he warns. “There’s no cure. Once the lungs are damaged, treatment is limited to symptom management with medications like bronchodilators, steroids, or, in severe cases, lung transplants. That’s why prevention is critical — it’s the only real defense.”
The Hidden Dangers in Your Favourite Vape Flavour
But diacetyl isn’t the only concern. Flavoured vapes expose users to a complex mix of chemicals, many of which have not been thoroughly studied for long-term inhalation risks.
“These include volatile carbonyls like formaldehyde and acetaldehyde — both found in e-cigarette vapour,” says O’Shea.
He emphasizes the scale of chemical exposure in vaping is significant — and potentially far more dangerous than many users realize.
“Experts estimate that there are over 180 different flavouring agents used in e-cigarette products today,” Professor O’Shea explains. “When these substances are heated, they can break down into entirely new compounds — many of which have not been tested for inhalation safety.”
So while diacetyl is a well-known danger, it’s far from the only one.
“Because vapers inhale a mix of so many chemicals, it’s difficult to pinpoint diacetyl as the sole cause of the disease in any individual case,” he notes. “But that doesn’t diminish the well-documented risks of inhaling it.”
Even if diacetyl isn’t the only factor, the cumulative exposure to a wide array of chemicals and their breakdown products could significantly raise the risk of developing popcorn lung and other serious respiratory conditions.
Banned in Some Places — But Still Widespread
Diacetyl has been banned from e-cigarettes in the EU and UK, but it’s still found in unregulated or illegal products — and remains completely legal in many countries, including the United States.
This means that even if you believe you’re vaping “safely,” you could still be inhaling harmful chemicals that cause permanent damage to your lungs.
And once the damage is done, there’s no turning back.
