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.

Implemented controls lowered exposures to butter-flavoring chemicals and decreased lung disease risk for much of the plant workforce. Some workers with continuing potential for intermittent, short-term peak and measurable time-weighted exposures remain at risk and should use respiratory protection and have regularly scheduled spirometry to detect rapid lung function declines that may be work-related. Close follow-up of such workers is likely to yield additional information on risks due to peak and time-weighted exposure levels.

Workers who manufacture or use flavorings can be subjected to repeated intense exposures to flavoring chemicals. Affected workers can progress to severe fixed airways obstruction in as little as 7 months. Since medical treatment is generally ineffective, early identification of affected workers and removal from further exposure, along with control of exposures to protect coworkers, are essential to minimize this hazard.