Background Worker participation allows employees to exercise control over their work conditions and enhances the efficiency of occupational safety and health management in the workplace. It is common for individual employees to participate through collective power, such as by organising a labour union. However, the associations between the levels of workers’ collective power and occupational safety and health (OSH) outcomes have not been empirically examined.

Methods By utilising data from a nationally representative sample of paid employees in Taiwan, this study examined the distribution of employees’ collective power across socio-demographic categories and work characteristics. The associations of collective power with self-rated health, self-reported occupational injuries, and mental health were examined.

Results A total of 9180 men and 7269 women aged 25–65 years were studied. The results indicated that employees with lower educational status, lower working hours than 40 per week, fix-termed contract, and piece-rated or time-based payment reported lower collective power. The collective power increased along the size of the enterprise. Those who had lower job control, higher job demands, higher employment insecurity and lower workplace justice were found to possess lower collective power. The results of multivariate regression analyses showed that lower collective power were associated with higher risks for poorer self-rated health, higher occupational injuries, poorer mental health, after adjusting sex and age. The odds ratios were 1.89, 1.58, and 1.72 respectively. The associations were found to be attributed to the correlation of higher job insecurity and poor workplace justice with lower levels of collective power.

Conclusion Findings from this study call for more attention on the importance of collective power of employees in the occupational safety and health management and its influence on workers’ health.