Evaluation of flavorings-related lung disease risk at six microwave popcorn plants.

OBJECTIVE After investigating fixed airways obstruction in butter flavoring-exposed workers at a microwave popcorn plant, we sought to further characterize lung disease risk from airborne butter-flavoring chemicals. METHODS We analyzed data from medical and environmental surveys at six microwave popcorn plants (including the index plant). RESULTS Respiratory symptom and airways obstruction prevalences were higher in oil and flavorings mixers with longer work histories and in packaging-area workers near nonisolated tanks of oil and flavorings. Workers were affected at five plants, one with mixing-area exposure to diacetyl (a butter-flavoring chemical with known respiratory toxicity potential) as low as 0.02 ppm. CONCLUSIONS Microwave popcorn workers at many plants are at risk for flavoring-related lung disease. Peak exposures may be hazardous even when ventilation maintains low average exposures. Respiratory protection and engineering controls are necessary to protect workers.