Nine former workers from a microwave popcorn packaging plant were reported to have a severe lung disease, bronchiolitis obliterans, but no recognized causes of this rare condition were evident in the plant. At the request of the Missouri Department of Health, staff of the National Institute for Occupational Safety and Health have investigated exposures and health outcomes at the company. Industrial hygiene assessments divided the plant into four work areas based on anticipated exposure levels to dust and volatile organic chemicals from artificial butter flavorings. Respirable dust concentrations from salt dumping operations were about 10-fold higher in the area in which flavorings were mixed compared to the office and outdoor work areas. Diacetyl, the predominant ketone in the plant, was present in concentrations 17 times higher in the mixing area compared to the microwave packaging area, 100 times higher compared to the warehouse and polyethylene packaging area, and 1000 times higher compared to the office and outdoor areas. In late October 2000, 117 current workers (87%) participated in health questionnaire interviews, spirometry, diffusing capacity, and chest x-rays. Plant employees had 2.6 times the rates of chronic cough and shortness of breath compared to national data, adjusted for smoking and age group; younger employees who had never smoked had rates about five times higher than expected from national rates. Overall, plant employees had 3.3 times the rate of obstructive spirometry abnornalities compared to national adjusted rates; never smokers had 10.8 times the national expected rate. Worker reports of physician-diagnosed asthma and chronic bronchitis were about twice as frequent as expected from national data, with a 3.3-fold excess of chronic bronchitis in never smokers. Microwave popcorn production workers had statistically higher rates of regular trouble with breathing and unusual fatigue, compared with workers in two lower exposure groups. Strong exposure-response relationships existed between quartile of estimated cumulative exposures to diacetyl and respirable dust and frequency and degree of airway obstruction. The survey findings are best explained by work-related bronchiolitis obliterans in relation to exposures arising in the mixing room but widely disseminated through other areas of the plant We recommend extensive primary, secondary, and tertiary prevention efforts for all current and former workers.
Pulmonary-function-tests; Pulmonary-system-disorders; Volatiles; Organic-chemicals; Respirable-dust; Respiratory-irritants; Respiratory-system-disorders; Ketones; Chronic-inflammation; Medical-screening; Employee-exposure; Bronchial-asthma; Smoking; Region-7; Fatigue; Food-additives; Food-colors; Food-processing; Chest-X-rays; Airway-obstruction; Lung-irritants