Objective To analyze the health outcomes of respiratory system induced by man-made vitreous fibre insulation wools with different occupational exposure profiles.
Methods This study enrolled 99 workers from two rock wool plants with an exposure profile of low number concentration of fibre and low gravimetric concentration of total dust and 98 workers from two glass wool (and slag wool) plants with low number concentration of fibre and high gravimetric concentration of total dust as exposure groups; another 141 and 100 workers only exposed to noise were selected as corresponding control groups. All subjects accepted pulmonary function tests and nasopharynx examinations. Incidence data of pneumoconiosis, lung cancer, malignant mesothelioma, and other tumors in the four plants were retrospectively collected.
Results The detection rate of restrictive pulmonary dysfunction in the rock wool exposure group was 28.3%, significantly higher than that of the control group (9.9%)(P<0.05), and showed a linear trend with exposure age (P<0.05). The detection rate of restrictive pulmonary dysfunction in the glass wool exposure group was 14.3%, not significantly different from that of the control group (8.0%)(P>0.05), and showed no linear trend with exposure age (P>0.05). The detection rates of chronic rhinitis in both exposure groups were 7.1%, not significantly different from those of the control groups (5.7% and 6.0%)(P>0.05). The detection rates of chronic pharyngitis in the rock wool exposure group (31.3%) and glass wool exposure group (52.0%) were significantly higher than those of the correspongding control groups (5.7% and 6.0%, respectively)(P<0.05). Exposure to rock wool/glass wool and smoking may be the risk factors of chronic pharyngitis. Two cases of mineral wool pneumoconiosis were detected, but no cases of lung cancer, malignant mesothelioma and other cancers were seen.
Conclusion Exposure to man-made vitreous fibre insulation wools can harm worker's pulmonary ventilation function, mainly restrictive pulmonary dysfunction, and may also induce lung fibrosis. Rock wool that is high in concentration of total dust can induce more significant pulmonary function impairment than glass wool with a lower concentration does.
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