Occupational asthma and extrinsic alveolitis due to isocyanates: current status and perspectives.

Isocyanates are used for the large scale production of polyurethane polymers, which have an almost endless variety of applications in the manufacture of flexible and rigid foams, elastomers, adhesives, and surface coatings. Acute or chronic exposure to high concentrations of isocyanates can result in respiratory health hazards through a direct irritant effect. Isocyanates are of special interest, however, because, in some exposed workers, they can cause occupational asthma or extrinsic alveolitis through an apparently sensitising mechanism.Because of their wide industrial use, isocyanates are the principal cause of occupational asthma which is now the most common respiratory disease linked to the working environment. This review focuses on recently studied aspects of occupational asthma and extrinsic alveolitis related to exposure to isocyanates.