Respiratory symptoms and lung function in foundry workers exposed to low molecular weight isocyanates

Abstract

This study investigated the prevalence of ocular and respiratory symptoms and lung function in foundry workers exposed to isocyanic acid (ICA) and methyl isocyanate (MIC). Foundry workers (n = 64) using the Hot Box binder technique and referents (n = 134) completed two questionnaires and a spirometry before and after a day shift. Findings were analyzed relating to exposure measurements of ICA, MIC, and formaldehyde. Exposed workers reported more frequently ocular irritation and coughing. Pre-shift lung function was lower than predicted in both groups of workers, and was not associated with exposure duration. Decrease in lung function over shift was more pronounced in exposed workers, but this was not associated with quantitative measures of the exposures. An increased prevalence of ocular and respiratory symptoms, as well as a small decrease in lung function over shift, was observed among exposed workers. No associations with exposure to monoisocyanates and formaldehyde were seen, thus suggesting that other irritants in the foundry environment might be the cause. The effects seemed to be small and not clinically relevant on an individual level. Further studies using a follow-up design may be warranted.