Objective The occupational health examination data of dust-exposed workers in a coal mine was analyzed to observe the adverse effects of coal dust on workers' health and provide orientation for early prevention of coal workers' pneumoconiosis.

Methods According to the exposure condition, 2 224 examined workers were divided into 3 groups. The exposure level of workers in Group 1 was heavy and the concentration of coal dust at workplaces was higher, while the exposure level of workers in Group 2 was relatively low and the concentration of coal dust at workplaces was lower than national OELs. The workers in Group 3 exposed to little or no coal dust within the company. The data of 3 groups was compared and multivariate logistic regression analysis was performed to observe the affecting factors on abnormality of chest radiography and pulmonary function of the workers.

Results Among 2 224 workers, 54 occupational contraindications were found, including 10 pneumoconiosis cases. The multivariate logistic regression analysis showed that the workers in Group 1(heavy exposure) had a higher risk of suffering with abnormality of chest radiography and lung function, compared with workers in Group 2 and 3(P < 0.01). The workers with longer exposure time had a higher risk of suffering with abnormality of chest radiography and lung function(P < 0.01 or 0.05), and smoking played a very important role in it.

Conclusion Heavy exposure to coal dust causes serious problem about health of occupationally exposed workers. The coal mine company should strive continuously to improve working environment quality and reduce the exposure level of workers by all means.