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Does Diacetyl Cause Popcorn Lung from Vaping?

Jim McDonald
September 20, 2023

What is popcorn lung?

Popcorn lung is a slang name for a serious condition with the scientific name bronchiolitis obliterans, or obliterative bronchiolitis. Sometimes the name is abbreviated as BO, and it is occasionally called constrictive bronchiolitis.

Popcorn lung is caused when the smallest airways within the lungs (bronchioles) are scarred, and their capacity and efficiency are reduced. There is no cure for the condition except a lung transplant.

Bronchiolitis obliterans can result from a variety of medical and environmental causes. The bronchioles can become inflamed and damaged from viral, bacterial and fungal infections, or by inhalation of chemical particles. Although diketones like diacetyl are the chemicals most often associated with popcorn lung, the National Institutes of Health list several other chemicals that can cause it, including chlorine, ammonia, sulfur dioxide, and inhaled metal fumes from welding.

And despite being the only real popcorn lung cure, lung transplants themselves can cause it too. In fact, bronchiolitis obliterans syndrome (BOS) is the single largest cause of chronic lung transplant rejection.

What are the symptoms of popcorn lung?

In a bronchiolitis obliterans victim, the scarring of the lung tissue blocks the airways and prevents the lungs from functioning properly. The symptoms are very similar to those of chronic obstructive pulmonary disease (COPD), but bronchiolitis symptoms can appear within just 2-8 weeks, while COPD typically takes many years or even decades to develop. Early obliterative bronchiolitis symptoms include:

  1. A dry cough
  2. Shortness of breath
  3. Reduced activity tolerance
  4. Wheezing (without a cold or asthma)
  5. Fatigue

Although popcorn lung is an incredibly rare disease, the early symptoms are similar to a common cold. Over a period of weeks or months, those symptoms progress and become more severe. Eventually the disease causes a variety of severe problems with breathing and absorption of oxygen. Untreated, popcorn lung causes death from respiratory failure within months or years.

There is no cure for popcorn lung, but treatment can sometimes slow its progression. Depending on the cause, popcorn lung is sometimes treated with antibiotics, immunosuppressive drugs, or corticosteroids. Cough medication or oxygen may be given to help manage symptoms. Severe cases may require a lung transplant.

Popcorn lung can be difficult to diagnose. Although CT scans and pulmonary function tests can offer strong clues, the only truly reliable way to identify the disease is through a surgical lung biopsy. And sometimes multiple biopsy samples are required to be certain.

Why is it called popcorn lung?

In 2002, the Centers for Disease Control and Prevention (CDC) documented eight cases of lung disease in employees who had worked in a Missouri popcorn factory between the years 1992 and 2000. Investigation showed that those with the worst lung damage had spent considerable time mixing a flavoring chemical called diacetyl with hot oil in large industrial vats.

Although the popcorn workers who were diagnosed with obliterative bronchiolitis had severe and irreversible lung damage, the National Institute for Occupational Safety and Health (NIOSH, an agency within the CDC) found that the workers at the factory showed a spectrum of injury to the lungs probably caused by the flavoring chemicals. Not every affected employee had untreatable lung obstruction.

The diagnosis of bronchiolitis obliterans in the widely publicized cases earned the disease the nickname popcorn lung. In fact, bronchiolitis is so associated with the popcorn factory cases that many people don’t know that popcorn lung can have many causes other than diacetyl.

Popcorn lung vaping diacetyl

What is diacetyl?

Diacetyl is an organic compound that occurs naturally in fermented products like alcoholic drinks and in cultured milk products. It’s also found naturally in some fruits and tobacco. Diacetyl is widely used as a flavoring in processed foods because of its buttery taste and ability to enhance sweet flavors. It was commonly used as an additive in “butter-flavored” microwave popcorn, consumed by millions the world over. After the popcorn lung investigations, most manufacturers stopped using butter flavoring with diacetyl.

Diacetyl is also known as 2,3-butanedione. It’s part of a chemical family called diketones. The other popular diketone used as a flavoring is acetyl propionyl, also known as AP or 2,3-pentanedione. A related flavoring chemical, acetoin, is a ketone (but not a diketone), and has similar properties.

Diacetyl and AP pose no known dangers when ingested. The FDA designates both chemicals “generally recognized as safe” (GRAS), meaning there have been no observed negative health outcomes from eating or drinking them. However, inhaling diacetyl and similar flavorings—at least in large quantities, like the popcorn factory mixers did—can cause irreversible lung damage.

Popcorn lung, or bronchiolitis obliterans, is famously caused by industrial diacetyl fumes, and acetyl propionyl is likely just as dangerous. The CDC refers to obliterative bronchiolitis and related lung conditions as “flavorings-related lung disease,” and has published occupational exposure standards for diacetyl and other diketones.

Is there diacetyl in vapes?

There can be diacetyl in e-liquid. It’s not always present, but it is in some e-liquids on the market. The source of diacetyl and AP in e-liquids is the flavorings used to make them. The most obvious ones are e-juices with buttery flavors, like custards and other sweet desserts. But some candy- and fruit-flavored e-liquids and even tobacco flavors can also contain diketones like diacetyl.

E-cigarette users have had concerns about diacetyl and health to vapers almost since vaping began, but the topic was first addressed scientifically in a 2014 paper by cardiologist Konstantinos Farsalinos and three colleagues. Their research found diacetyl and AP in a large number of sweet-flavored e-liquids, and deemed the diketones “an avoidable risk.” After the study, there was heated debate in the vaping community that resulted in many companies—but not all—reformulating their products. And not all vapers even wanted them to.

For vapers concerned about diacetyl, there are some companies recognized for their diketone-free formulations. And if you live in the U.K. or European Union, diacetyl is prohibited as an ingredient in nicotine-containing e-liquid.

Does vaping cause popcorn lung?

There has never been a proven case of popcorn lung caused by vaping, although there have been many news stories that suggest vaping can cause it. There’s no evidence to support vaping as a cause of popcorn lung, in any vaping studies or otherwise, but maybe diacetyl exposure from cigarette smoking may provide some insight about the risk. Cigarette smoke contains at least 100 times as much diacetyl as the highest levels in any vaping product, yet smoking is not associated with popcorn lung.

Despite the one billion smokers in the world who inhale diacetyl regularly from cigarettes, no smoker has been diagnosed with popcorn lung. In fact, the few smokers known to have contracted popcorn lung were workers in a popcorn factory. According to NIOSH, smokers with bronchiolitis obliterans exhibit a discernibly more severe kind of lung damage than smokers with the usual (though still terrible) smoking-caused respiratory diseases like emphysema or chronic bronchitis.

Despite the well-known risks of smoking, popcorn lung is not one its outcomes. Of course, lung cancer, heart disease, and chronic obstructive pulmonary disease (COPD) are associated with smoking from inhalation of carcinogenic compounds, tar, and carbon monoxide. But vapes don’t involve combustion, so they don’t produce any tar or carbon monoxide—and in the worst-case scenario, they only contain about one percent of the diacetyl that’s in cigarettes. While almost anything is possible, there’s simply no evidence that vaping causes popcorn lung.

Smokers created vaping without help from the tobacco industry or anti-smoking crusaders, and I believe vapers have the right to continue innovating to help themselves. My goal is to provide clear, honest information about the challenges vaping faces from lawmakers, regulators, and brokers of disinformation. I’m a member of the CASAA board, but my opinions aren’t necessarily CASAA’s, and vice versa. You can find me on Twitter @whycherrywhy
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Eli Law
Eli Law
4 years ago

A Canadian teen recently contracted popcorn lung from vaping. How is that possible if vapers are exposed to far less levels of diacetyl compared to cigarettes but no one has gotten popcorn lung from smoking?

Jeremy Mann
Staff
Jeremy Mann
4 years ago
Reply to  Eli Law

No Canadian teen contracted popcorn lung from vaping retail nicotine products. Find the link to whatever you THINK told you that and re-read it. I’m sure you don’t want to be spreading false rumors.

Eli Law
Eli Law
4 years ago
Reply to  Jeremy Mann

Here is the case report – https://www.bbc.com/news/amp/world-us-canada-50494871

It states that he was heavily vaping flavored nicotine products. I’m not too sure if they were “retail nicotine products” because they were thrown out. This injury is different than the ones that have happened in America. For this one, from the lung CT scans, vitamin e acetate is not present, so a knew substance had to have caused this like diacetyl.

Jeremy Mann
Staff
Jeremy Mann
4 years ago
Reply to  Eli Law

From your link, “The boy had vaped daily for five months using flavoured cartridges and regularly added THC – the psychoactive ingredient in cannabis – to his vaping fluid. His parents told the doctors he also had a habit of inhaling deeply when vaping.” How is the “regularly added THC” not THE story? Let’s flesh out some things. What we know: *This teen (a 17-year-old) altered e-liquid and made a homebrew of unknown constituents *THC cannot be added to e-liquid without a cutting agent *Any number of things can be added to cut THC to make it fluid enough to… Read more »

Eli Law
Eli Law
4 years ago
Reply to  Jeremy Mann

Wow, okay fair point. I appreciate you taking your time to explain this to me. I have some more questions though if you don’t mind me asking. So you can’t add thc to vapes without another substance to make it vapable. This teen was adding thc to his vapes but was adding another unknown substance to make it vapable, that we don’t know about. My source said that they were “thrown away”. How could he have a popcorn lung like injury? The lung x rays we are seeing from this teen look almost exact to what the popcorn workers looked… Read more »

Jeremy Mann
Staff
Jeremy Mann
4 years ago
Reply to  Eli Law

It’s maddening to see these stories coming out constantly with so little in the way of real research or a simple investigative approach. They start with the idea that vaping e-liquid is the culprit and work their way back from there. So why does it happen like that? My belief is that media nowadays MUST act at any “opportunity” to throw vaping e-liquid under the bus; not to figure out what really happened. For instance, almost EVERY story on the news I’ve seen about lung injuries caused by vaping black market THC oil shows people blowing clouds of vapor from… Read more »

Eli Law
Eli Law
4 years ago
Reply to  Jeremy Mann

Thank you so much for explaining this to me. I have a friend and we are in a vaping debate at the moment, this really informed me. So what you’re basically saying is that regular nicotine vaping did not cause this, it was most likely the unknown substance he was using to add thc, since thc itself cannot be vaped, another substance has to be added to make it vapable.
Right?

Jeremy Mann
Staff
Jeremy Mann
4 years ago
Reply to  Eli Law

What I’m saying is that the doctors don’t know what caused it, and they’re not really trying to figure it out. The case study made no mention of how he added THC, if they tested the liquids from the retailer, or if they contacted any other customers. This story is basically a joke in the way it’s being presented. This is not how medical mysteries are handled. This is how propaganda works. We do know that no case like this has EVER occurred in any medical literature from nicotine vaping, despite millions of vapers across the globe vaping flavors for… Read more »

Eli Law
Eli Law
4 years ago
Reply to  Jeremy Mann

Fair point man. I have 1 last question before you go. My friend claims that his parents have contradicted popcorn lung from smoking cigarettes. I explained to him that smoking does not cause popcorn lung but still doesn’t seem to understand. Can you go in depth and explain why smokers, even with diacetyl levels 100 times higher than vaping, are not getting popcorn lung?
Thank you

Jeremy Mann
Staff
Jeremy Mann
4 years ago
Reply to  Eli Law

Not sure what you’re saying about “contradicted popcorn lung….” Maybe you meant contracted? I don’t know. Either way, my best guess based on the original cases of popcorn lung would be that the amount of diacetyl in cigarettes isn’t enough to cause it. Have you heard the saying, “the dose makes the poison”? You do realize that the diacetyl in the popcorn lung factories where this originally happened was coming from workers without masks hovering over huge vats of diacetyl, right? And unlike in vape juice or in cigarettes where the measurements are in micrograms, those original cases where the… Read more »

Eli Law
Eli Law
4 years ago
Reply to  Jeremy Mann

Alright, thank you for answering my questions and explaining them clearly.
I will let you know if I have any additional questions on this topic. You have a good rest of your day bro!

Jeremy Mann
Staff
Jeremy Mann
4 years ago
Reply to  Eli Law

Hi Eli,

Just posting this here in case you hadn’t seen it. Did a Canadian Teen Get Popcorn Lung from Vaping?

Daniel Hehir
Daniel Hehir
5 years ago

Great information thank you!

Gary
Gary
5 years ago

Thanks so much for the reassuring information. I had looked up this subject on Web MD and it mentions diacetyl but not how unlikely it is to get the condition. Your information is far more comprehensive and reassuring.
Maybe submit your article to them, so as to stop frightening people.
Many thanks,
Gary

Jack Stewart
Jack Stewart
4 years ago

Hi, so I have a question that’s been on my mind and I’m in a debate about popcorn lung and vaping with one of my friends. I’ve done research, and found that popcorn lung is not a reportable disease. So if one is diagnosed, they do not have to report it and let everyone in the world know, they could just keep it confidential and no one would ever know. How could you say that not one single vaper or smoker has never gotten diagnosed with popcorn lung, if it’s not a reportable disease? Thousands could be getting it but… Read more »

Jack Stewart
Jack Stewart
4 years ago
Reply to  Jim McDonald

Thank you for answering this. Could you send me the link where it states “not even a lifetime of smoking is a risk factor for popcorn lung” from the CDC? So what you’re telling me is besides the point that popcorn lung is not reportable, that wouldn’t stop doctors from reporting it as a health risk?

Gary Balkam
Gary Balkam
4 years ago

I have been telling people that for years…even counting the cases of popcorn lung contracted in that popcorn factory, odds are 1 in 1.25 BILLION. Mind you, all 6 were working in the same area of the same factory and none wore protective filter masks.