A prospective and immunologic study of factory workers exposed to TDI (toluene diisocyanate).

Thirty factory workers whose annual exposure to TDI amounted to 280 hours were examined. Seven of them had been removed from their jobs for presenting respiratory symptomatology and a further five were removed for presenting bronchial asthma. Their medical histories were consulted and further measures were taken such as a radiological thorax study, total IgE, TDI, MDI and HDI RAST, a basal spirometric study and finally a provocation test. The Rast proved negative in every case. In the spirometric study carried out on the provocation test, four cases showed a significant decrease in the FEV1 over 20% and over 40% in the FMEF and PEFR. There was no connection between the four patients who presented an elevated total IgE and the four who presented a positive provocation test. The provocation test proved negative in five of the seven patients removed from their places of work. Two of the four workers who responded positively to the provocation test remained in their places of work during the TDI foam test without showing any symptoms. The patients who presented symptoms did not appear to present bronchial obstruction during the provocation test. Nonetheless, patients who seemingly had not shown any symptoms presented what appeared to be bronchial obstruction.