A jury recently awarded $25 million to a man who developed bronchiolitis obliterans—often called “popcorn lung”—after regularly using butter-flavored PAM cooking spray at home. The core allegation: buttery flavor chemicals created an inhalation hazard during routine cooking.
This case is striking because it pulls a problem most people associate with factories and food plants into an everyday setting: the kitchen.
What is “popcorn lung,” really?
Bronchiolitis obliterans is a serious, irreversible disease of the small airways. The nickname “popcorn lung” comes from well-documented workplace clusters in microwave popcorn and flavoring production facilities, where workers inhaled airborne butter-flavor chemicals over time.
The key concept is simple:
This isn’t primarily a food issue. It’s an air issue.
FDA “GRAS” is about eating, not breathing
A lot of confusion comes from a single phrase: Generally Recognized as Safe (GRAS). That designation is about ingestion—what happens when you eat an ingredient at expected levels.
But the body doesn’t handle chemicals the same way through different routes of exposure. What may be reasonable to ingest can be problematic to inhale—especially when it’s concentrated, heated, aerosolized, and delivered deep into the lungs.
In other words:
“Food-safe” does not automatically mean “breath-safe.”
How kitchens can become exposure scenarios
This is why the PAM case matters. It highlights a mechanism that industrial hygienists have warned about for years:
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Aerosols (sprays create fine droplets you can inhale)
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Heat (hot pans increase evaporation and aerosol dynamics)
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Repeated use (dose over time matters)
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Poor ventilation (exposures rise quickly in small or under-ventilated spaces)
Put those together and you can turn a “buttery flavor note” into an inhalation exposure pathway.
Substitution isn’t the same as solving the problem
A common response to diacetyl concerns has been substitution: replacing diacetyl with 2,3-pentanedione (and sometimes acetoin) in buttery flavor systems.
On paper, this can look like progress. In practice, it may not be.
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2,3-pentanedione is chemically similar to diacetyl and has been flagged by NIOSH as a relevant inhalation concern.
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The argument that “it’s higher boiling, so it’s safer” often falls apart in real cooking conditions. Cooking temperatures are well above the boiling points of both compounds, and aerosol sprays create enormous surface area. When you’re spraying and heating, volatility differences can matter less than people assume.
If the substitution still produces an inhalable mix of reactive flavoring compounds at meaningful concentrations, the hazard may persist—just with a new name.
Expect more problems if we treat substitutions as solutions without measuring real exposures.
“But these chemicals occur naturally…”
They do—and that matters for context.
Diacetyl and 2,3-pentanedione occur naturally in foods many of us love: butter, coffee, and more. For most people, normal dietary intake in reasonable portions is likely not the issue.
The bigger concern is breathing concentrated vapors/aerosols repeatedly, especially in settings where chemicals are heated, aerosolized, and used often.
Also important: “natural vs synthetic” doesn’t determine safety. The lungs don’t care where a molecule came from.
Synthetic flavorings can be part of healthier food—if used safely
There’s a bigger point here that gets lost in the fear: synthetic ingredients can give food formulators tools to improve nutrition.
For example, a carefully engineered buttery flavor note can reduce reliance on animal fats and help lower saturated fat content—potentially improving public health outcomes.
But “useful” doesn’t mean “risk-free.” The path forward is not banning chemistry. It’s learning how to use it safely.
The practical takeaway: stop guessing—measure exposure
If you’re working with flavorings, operating food production, troubleshooting indoor air concerns, or simply worried about what’s in your breathing zone, the safest approach is the same:
Measure the exposure. Don’t assume it.
At Air by CCSquared, we offer air samplers and lab analysis to quantify exposure to diacetyl and other 1,2-diones (including 2,3-pentanedione) so you can make decisions based on data—not fear.
Link: https://airbyccsquared.com/products/diacetyl-and-related-diones
Bottom line
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The PAM verdict underscores that flavoring inhalation hazards aren’t confined to factories.
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“GRAS” is ingestion-focused; inhalation is a different pathway.
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Substitution (diacetyl → 2,3-pentanedione) doesn’t automatically solve the hazard.
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Natural vs synthetic doesn’t change risk; concentration and route do.
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We can get the benefits of modern formulation if we pair it with ventilation, thoughtful use, and measurement.