Among 19 workers in a polyurethane foam production plant, visual disturbances ("foggy vision", "blue haze", and sometimes halo phenomena) were reported on a total of 47 occasions by five workers over 11 weeks. The symptoms were associated with triethylamine exposure. Time-weighted average levels of 12 to 13 mg/m3 were recorded at work operations associated with symptoms, and 4 to 5 mg/m3 at other tasks. Twice as high peak levels were recorded. A detailed medical examination of the five affected workers in a free interval did not reveal any signs of permanent eye disease.