Ventilatory function in workers exposed to low levels of toluene diisocyanate: a six-month follow-up.

115-120. Thirty-four workers exposed to toluene diisocyanate during production of polyurethane foam were examined with a respiratory questionnaire and tests of ventilatory capacity. The tests of pulmonary function were conducted on Monday morning and afternoon and on Tuesday morning and afternoon. Twenty-eight of these 34 workers had been examined with the same tests six months earlier. On Monday a mean change in the one-second forced expiratory volume (F.E.V.) of –0·16 l. occurred that did not return to the baseline value (Monday a.m.) on Tuesday morning. A statistically significant decrease in all the measurements of ventilatory capacity except the forced vital capacity occurred over the six months in the 28 workers. The F.E.V. fell an average of 0·14 l. and flow rates at 75%, 50%, 25%, and 10% of vital capacity also decreased significantly. There was a highly significant correlation coefficient (r = 0·72) between one-day changes in F.E.V. (measured six months earlier) and six-month changes in F.E.V.. Workers with respiratory symptoms (cough and/or phlegm) demonstrated greater falls in F.E.V. than did asymptomatic workers. All air concentrations of toluene diisocyanate measured during this study were below the threshold limit value (0·02 p.p.m.).