Bronchiolitis obliterans is back in the news again, and this time the devastating lung condition is tied to the coffee industry. Our readers may recall the disease by its nickname, “popcorn lung,” due to its association with numerous microwave popcorn plant workers who developed the devastating disease in the early 2000s. Consumers also developed the rare condition after frequently eating microwavable popcorn and coming in contact with flavoring additive fumes.

Bronchiolitis obliterans is known to be caused by two toxic flavoring additives called diacetyl and 2,3 pentanedione. These chemicals are naturally occurring volatile organic compounds but are also synthetically made as food additives to mimic the taste of butter. As a result, they are incorporated in foods we consume every day. Unfortunately, inhalation of these chemicals at high concentrations can cause quick, irreversible lung damage, although symptoms typically appear later. Bronchiolitis obliterans clogs small air pathways in the lungs and forms scar tissue that severely restricts breathing. The disease is incurable, and without a lung transplant, is oftentimes fatal.

Prompted by an investigative report by the Milwaukee Journal Sentinel detailing how coffee industry workers could be in danger of developing potentially deadly lung disorders, the U.S. Centers for Disease Control and Prevention (CDC) started testing the air inside a dozen coffee roasting facilities across the country. The results showed very high concentrations of the two flavoring additives in the facilities. The National Institute for Occupational Safety and Health (NIOSH) conducted its first study at Madison, Wisconsin-based Just Coffee last July, and found extremely high levels of diacetyl and 2,3 pentanedione throughout the facility. Interestingly, the facility did not use the artificial flavoring in its coffee.

Tests conducted by an industrial hygienist hired by the Journal Sentinel in Just Coffee and another Wisconsin coffee roaster found that diacetyl levels exceeded the government’s maximum safety level by four times. Workers at Just Coffee were typically exposed to 7 parts of diacetyl per billion – surpassing the CDC’s limit of 5 parts per billion. Diacetyl concentrations inside storage bins containing roasted beans contained 7,000 parts per billion, prompting the CDC to explicitly warn workers to refrain from sticking their heads inside the containers or remaining in their presence for long periods of time.

Last year, five coffee roasters – from cafes to midsize facilities – agreed to share their medical tests with the Journal Sentinel and have the results reviewed by three doctors with experience in diacetyl-related illnesses. Of the five workers, four had lung tests or symptoms consistent with hazardous exposure.

Diacetyl and 2,3 pentanedione are used in a number of applications, and could be a major hazard in the manufacturing or cooking of the following: margarine, shortening, oil sprays, artificial butter substitutes, microwave popcorn, potato chips, corn chips, crackers, cookies, chocolate, cocoa-flavored products, candy, gelatin deserts, flour mixes, flavored syrups, prepackaged frosting, sauces, soft drinks, chewing gum, ice cream, starter cultures used to make butter, beer, wine, and now – in coffee.

Lawyers in our firm are actively investigating cases where a diagnosis of bronchiolitis obliterans has occurred. Oftentimes, the disease is misdiagnosed as asthma, chronic bronchitis, emphysema or pneumonia. If you have any questions about these cases, contact Parker Miller at 800-898-2034 or

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