Effects of blasting fumes on exposure and short-term lung function changesin tunnel construction workers

Objectives This study attempts to determine the effects of exposure to blas ting fumes and its influence on the lung function of tunnel workers. Methods Two groups of tunnel workers, one using ammonium nitrate fuel oil ( ANFO) as the explosive and the other using size-sensitized emulsion (SSE), with 24 workers per group, were compared with a reference group (N=34) with low exposure. Spirometry was used to determine lung function. Personal exp osure to total and respirable dust, alpha-quartz, volatile organic compound s, oil mist and vapors, formaldehyde, nitrogen dioxide, and carbon monoxide was measured. Results The ANFO workers were more exposed to all the agents than the refer ence group and more exposed than the SSE workers to all the agents except t otal dust and carbon monoxide. The SSE workers were significantly more expo sed to total dust and alpha-quartz than the reference group. High peak expo sures to nitrogen dioxide (up to 20 ppm) occurred for the ANFO workers in c ontrast to the SSE workers, whose exposure did not exceed 2 ppm. The lung f unction of the ANFO workers significantly decreased by 3% for forced vital capacity, 7% for forced expiratory volume in 1 second, and 8% for forced ex piratory flow rate from 25% to 75% of the forced vital capacity over the 11 -day period. The changes were reversible. There were no significant changes among the SSE workers and the outdoor workers. The ANFO workers had a sign ificant decrease in FEV1.0 when compared with both the SSE and outdoor work ers. Conclusions Tunnel workers using ANFO explosive show a temporary reduction in lung function, whereas those using SSE do not. The most likely explanati on for the observed changes is peak exposures to nitrogen dioxide.