Purpose of review: Since the initial report of bronchiolitis obliterans in microwave popcorn workers, exposures to flavoring substances have been identified in a variety of food and flavor manufacturing facilities and in the consumer market. Attempts to decrease the risk of lung disease have included the use of flavoring substitutes; however, these chemicals may cause similar injury. This article reviews recent flavoring exposures and data on the pathogenesis, clinical characteristics, and surveillance of flavoring-induced lung disease.
Recent findings: Diacetyl and 2,3-pentanedione exposures have occurred in food production facilities that make cookies, cereal, chocolate, and coffee. Airborne levels often exceed proposed occupational exposure limits. Cases of biopsy-proven bronchiolitis obliterans in heavy popcorn consumers have also been reported. New data demonstrate the presence of diacetyl and 2,3-pentanedione in flavored nicotine liquids used in electronic nicotine delivery systems.
Summary: Diacetyl substitutes cause similar peri-bronchiolar fibrotic lesions in animal studies. Their use may continue to place workers at risk for flavoring-induced lung disease, which may present in forms beyond that of fixed airflow obstruction, contributing to delays in identifying and treating patients with flavoring-induced lung disease. Engineering controls, medical surveillance and personal protective equipment can limit flavorings exposure and risk for lung disease.