Work place challenge: spirometric response in polyurethane (isocyanate) paint workers.

: In industrialised countries, isocyanate is probably the most common cause of occupational asthma. The present study was conducted to see the effect on FEV1 in workers who were directly exposed to isocyanate. One hundred and fourteen workers of a rail coach factory who were involved in polyurethane paint spray were studied. Spirometry was done three times, first before starting the work, at two hours and then 6-8 hours after finishing the work to see immediate, late and dual responses. Positive response was considered when there was fall of 20% or more in forced expiratory volume in 1 second (FEV1) from base line. Sixteen per cent of the workers exposed to isocyanate developed immediate reaction, 10% developed late reaction and 6% developed dual reaction. Non-smokers were more prone to develop late and dual responses.