Respiratory Symptoms and Occupational Asthma in Polyurethane Foam Production Workers

Toluene diisocyanate (TDI) and methylene diphenyl diiso­cyanate (MDI) and hexamethylene diisocyanate (HDI) are heavily used in the production of polyurethane foams. Occupational asthma (OA) is reported in approximately 5% of chronically exposed workers. This study aimed to evaluate the effects of isocyanate exposure on lung function in foam produc­tion workers in two different factories. Respiratory status was evaluated by a questionnaire modified from the occupational asthma report of ATS, physical examinaton and pulmonary function tests. Pulmonary function was evaluated using a mobile spirometer.107 workers (1 female, 106 male) were included in the study. 77 of these were working in polyurethane foam production (49 in one, 28 in a second factory), 18 in a dye department and 12 (the control group) were working in the offices (mean age, 26, 30, 27.5 and 31, respectively). All 3 groups were comparable in age and smoking habits. There were also no significant differences in fre­quency of respiratory signs and symptoms. However, pulmonary function tests showed significantly lower forced expiratory vol­ume (FEV) and forced vital capacity (FVC) values in the polyurethane group. Of the 32 workers who had respiratory find­ings suggestive of asthma and who underwent peak expiratory flow (PEE) meter follow-up, 17 were found to show positive vari­ability. Non-specific bronchial provocation tests were performed on these 17 workers and 3 (all of them were polyurethane pro­duction workers) were diagnosed as occupational asthma (3.89%). The results of the study indicate a need for the screen­ing and monitoring of all polyurethane foam workers for iso- cyanate-related respiratory disorders and OA.