Bronchiolitis obliterans in workers exposed to flavoring chemicals.
Medical and environmental surveys at microwave popcorn plants and flavoring production plants have revealed a risk for bronchiolitis obliterans in workers exposed to flavoring chemicals. Workers in other food industries may also be at risk. This review summarizes the available information on disease characteristics and natural history and provides information on workplace characteristics associated with disease development. Investigations carried out in flavoring plants in California have identified severely affected current and former workers in four plants. Affected former workers have also been identified at a plant in the Netherlands that manufactured diacetyl, a predominant chemical in butter flavorings which has been implicated as a causal agent for lung disease in microwave popcorn workers. 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.