What is Diacetyl?
Diacetyl is a chemical used as an artificial food flavoring. It is often used to add flavor to candy, popcorn, and baked goods. Diacetyl is also present in many e-cigarettes sold in the United States.
The chemical is used in e-cigarettes for the same reason it is used in food: for flavoring. Diacetyl allows vaping companies to offer fruit, candy, and dessert flavors — flavors especially appealing to young people.
Diacetyl is safe to ingest. However, if inhaled, diacetyl may cause permanent lung damage and scarring.
Diacetyl inhalation may cause:
- Breathing problems
- Difficulty exercising
- Nose, mouth, and eye irritation
- Other respiratory diseases
- Popcorn lung
The presence of diacetyl in vape products is concerning to the U.S. Surgeon General, who noted the potential health risks in a 2016 report on vaping.
Quick Facts about Diacetyl and Vape Products
- Inhaling diacetyl was proven to cause popcorn lung in factory workers in 2002 by the NIOSH.
- In a 2015 Harvard study, over 75% of flavored vapes that were studied contained diacetyl.
- Diacetyl was banned from vape products sold in the European Union in 2016.
- Other flavoring chemicals used in vape products, like acetoin and acetyl propionyl, may also cause damage to the lungs.
Health Issues Related To Diacetyl
As of 2019, the U.S. continues to allow the use of diacetyl in vape products.
However, previous investigations by the Centers for Disease Control and Prevention (CDC) show that inhaling diacetyl in other contexts has led to lung damage. This, in turn, suggests that inhaling the chemical while vaping may also harm the lungs.
Diacetyl and Popcorn Lung
Bronchiolitis obliterans, nicknamed popcorn lung, is a rare disease in which the lungs’ airways become stiff and scarred.
Popcorn lung got its nickname after a notable outbreak in the late 1990s and early 2000s. In this instance, workers at microwaveable popcorn factories developed the disease after breathing in diacetyl. The chemical was used heavily in these factories to make microwaveable popcorn taste more buttery.
Since e-cigarettes rely on diacetyl as a flavoring, organizations like the American Lung Association (ALA) are concerned that those who vape could also be at risk of developing popcorn lung.
Popcorn lung can cause the following symptoms:
- Difficulty breathing
- Dry cough
- Rapid breathing
- Shortness of breath
There is no cure for popcorn lung, and the disease gets progressively worse without treatment. Treatment typically consists of steroids and antibiotics if caught early. If the disease is caught late, a lung transplant may be necessary. Complications from popcorn lung may result in death.
Some vape companies like Rocket Fuel Vapes are warning their customers about diacetyl exposure.
Diacetyl and Other Health Issues
A 2019 study from Harvard found that inhaling diacetyl could damage cilia function in the lungs. Decreased cilia function has been associated with asthma and chronic obstructive pulmonary disease (COPD).
Diacetyl Substitutes and Vape Products
While diacetyl is the most notable flavoring chemical used in vape products, it can be combined with other chemicals or used as a substitute.
Diacetyl substitutes in vape products include:
- Acetoin: According to the U.S. National Library of Medicine, this chemical can contribute to respiratory issues after prolonged inhalation.
- Acetyl propionyl: A 2012 study in the journal Toxicologic Pathology showed that inhaling this chemical in high doses caused lung damage, respiratory tract inflammation, and death in rats.
Further, a study published in the American Journal of Pathology found that exposure to acetyl propionyl or diacetyl may cause airway fibrosis, a condition that causes difficulty breathing and scarring, in rats.
Other flavoring substitutes have also been linked to lung impairment. For example, the chemical cinnamaldehyde — used for creating cinnamon-flavored e-liquids — has also been linked to cilia damage by the American Thoracic Society.
Diacetyl, Vaping, and Investigations
As the health risks of diacetyl continue to be studied, researchers and government officials have expressed concerns about diacetyl in vape products.
In 2016, the U.S. Surgeon General published a report on the possible health risks of vaping. Included in the report was information about diacetyl and its substitutes.
Notable takeaways from the report included:
- A 2014 study from Penn State Brandywine and the Onassis Cardiac Surgery Center found diacetyl and acetyl propionyl in over 115 of 159 vape liquid samples. In many samples, these chemicals were found in dangerously high levels. The researchers concluded that diacetyl may pose a health risk for e-cigarette users.
- A 2016 Harvard study found diacetyl levels above laboratory limits of detection in 76% of the vaping e-liquid flavors that were sampled. In other words, because the diacetyl could be detected, the researchers recommended urgent action to evaluate if the chemical poses a risk.
The European Union (EU) banned diacetyl in e-cigarette products under the EU Tobacco Products Directive (TPD) of 2016. They determined that the level of diacetyl in e-cigarettes wasn’t safe for consumers within its jurisdiction.
Diacetyl Health Risks and Your Options
Diacetyl has already been shown to cause permanent lung damage in microwavable popcorn factory workers. Today, those who vape may also be at risk of harmful diacetyl exposure.
Vape products have already been linked to other serious health risks, such as teenage nicotine addiction and battery explosions.