Can We protect workers from developing the adverse respiratory effects of isocyanate exposure?
In this review, the authors have attempted to present the difficulty in defining a permissible exposure limit (PEL) to agents that act as sensitizers and may induce asthma-even at exposure levels less than the PEL. One approach to this relatively unaddressed problem may be to define the separate aspects of exposure to the specific sensitizing agent. The first effect is an accelerated rate of decline in lung function in nonsensitized individuals who are exposed to the agent (in this case the model used is isocyanates). The second effect is sensitization. Rules for developing a PEL might take this sensitizing effect into account, and this group of agents with such dual effects may be defined as "sensitizers." Exposure to agents with this designation would require special educational and surveillance initiatives to facilitate early detection. The elimination of sensitization may be a greater challenge. An important form of prevention is medical screening of exposed workers, yet it is unclear which screening approach best identifies workers with early isocyanate asthma.