Popcorn lung, or popcorn workers' lung, is officially known as bronchiolitis obliterans. It may also be referred to as constrictive bronchiolitis. It is a rare fixed obstructive lung disease where granulation tissue, or scar tissue, gradually obstructs the bronchioles, or airways. Although there are several other causes of bronchiolitis obliterans, it got its more common name because it can be caused by the repeated inhalation of diacetyl, which is used to flavor butter popcorn.
Bronchiolitis obliterans is indicated by a significantly reduced lung capacity, shortness of breath, wheezing and a dry cough. These symptoms are often misdiagnosed as asthma or pneumonia. It is caused by inhalation of toxic fumes, as well as viral infection, transplant rejection, and collagen vascular disease. In its advanced stages, it is not reversible and is only treatable by a lung transplant.
Although diacetyl is a chemical, it is a naturally occurring one that is found in butter, cheese and wine. It gives popcorn that “natural” butter taste that so many people love. Unfortunately, this seemingly harmless ingredient has caused serious illness in several popcorn factory workers, and in 2007, at least one consumer. The first documented cases occurred in Jasper, Missouri, in 2000 at the Gilster-Mary Lee plant where eight workers were diagnosed with popcorn lung. These workers had been exposed to diacetyl for an extended period of time while they were testing bags of microwave popcorn.
The National Institute for Occupational Safety and Health (NIOSH) conducted a study of 117 popcorn factory workers and found that they suffered higher rates of airway obstruction, chronic cough, shortness of breath, throat irritation, tightness in the chest and wheezing than what is found normally in the general population. Because diacetyl is a Food and Drug Administration-approved chemical for use as a flavoring, there were few precautions in place to protect workers from adverse effects. Since 2000, however, NIOSH has advised for implementation of safety measures for handling diacetyl in order to prevent future lung damage.
Although the Flavor and Extract Manufacturers Association has assured consumers that there is virtually no risk of developing popcorn lung from eating buttered popcorn, it has been recommended that manufacturers reduce the use of this chemical, mostly to protect plant workers. In 2007, ConAgra, the largest US popcorn manufacturer of brands such as Act II and Orville Redenbacher, joined the Weaver Popcorn Company in replacing the flavoring.
Since then, 19 factory workers have International Flavoring & Fragrances, which is the second biggest flavor manufacturer in the world, and won. In 2004, four of the workers were awarded $53 million US Dollars (USD) in settlements.
Although consumers have been assured that the flavoring is safe for consumption, one consumer has developed popcorn lung due to his above average consumption of microwave popcorn. Over a ten year period, he ate two bags of buttered popcorn every night, inhaling the bags as they came out hot from the microwave.