Bronchiolitis Obliterans Among Workers at Popcorn Factories Due To A Diacetyl Exposure. A unusually high incidence of bronchiolitis obliterans among workers at microwave popcorn factories is likely the result of their exposure to diacetyl, a new study says. The study, conducted by the National Institute for Occupational Safety and Health, (NIOSH) concluded that diacetyl, a chemical that gives microwave popcorn its butter flavor, needs further study so that workers in the flavorings and snack industry are no longer at risk of the fatal disease, also known as Popcorn Workers Lung.
Popcorn Workers Lung is a potentially life threatening ailment, for which the only cure is a lung transplant. The disease was thought to be limited to people working in the flavorings industry. But last July, Dr. Cecile Rhodes informed the Food & Drug Administration (FDA) that one of her patients had contracted the disease. The patient had been consuming several bags of butter-flavored microwave popcorn on a daily basis for at least 15 years. According to the Centers for Disease Control (CDC), this is the first report of Popcorn Workers Lung in a consumer. That victim has since filed a lawsuit against the company that produced the microwave popcorn he favored.
In 2003 and 2004, NIOSH found an association between the toxic substance and the development of Popcorn Workers Lung among hundreds of workers at six Midwestern popcorn factories. Last April, the CDC reported that workers at food flavoring factories, as well as popcorn plants, were at risk for the disease.
Diacetyl is Easily Vaporized in Microwave Popcorn Production
Diacetyl is easily vaporized at temperatures used in microwave popcorn production, which results in high concentrations in the workplace. The NIOSH research examined the acute toxicity of inhaled diacetyl in rats, and compared different exposure patterns. It was one of the very first studies to evaluate the respiratory toxicity of the chemical flavoring agent at levels relevant to human health. The researchers found that diacetyl — including just its vapors — can injure lungs.
In the study, lab mice were made to inhale diacetyl vapors over a three month time period. The mice developed lymphocytic bronchiolitis — a potential precursor of Popcorn Workers Lung. None of the mice, however, developed that disease.
In 2007, several makers of microwave popcorn, including ConAgra, General Mills and American Popcorn Co., took steps to remove diacetyl from their products. There has also been a movement to convince federal regulators to police the use of diacetyl in the workplace, but those efforts have had mixed results. The Occupational Safety and Health Administration (OSHA), which sets limits on how much of a dangerous substance a worker can be subjected to, said in 2000 that it had no standards for the flavoring and that it wasn’t a problem because the FDA considered diacetyl “safe.” For its part, the FDA has maintained that it has no jurisdiction to evaluate hazards posed by breathing vapors from food additives. It was only last year that OSHA started to investigate diacetyl exposure in snack food industry workers, and that agency is expected to look into setting standards for workers next month.