Which of the following is not a work item for preventing occupational diseases?

The correct choice is national insurance because it primarily refers to a system of contributions from workers and employers that provides financial support and benefits in the case of unemployment, sickness, or retirement, rather than directly addressing the prevention of occupational diseases. National insurance does not contribute to the direct management or mitigation of health risks in the workplace. In contrast, the other options specifically relate to actions and interventions aimed at protecting workers from health hazards.

Safety training sessions enhance employee awareness and knowledge about potential workplace hazards and safe practices. Regular health check-ups allow for the early detection of health issues that may arise from occupational exposure. Proper workplace ventilation is crucial in reducing exposure to airborne contaminants that could lead to respiratory conditions or other health problems associated with poor air quality. These actions are fundamental in mitigating risks and promoting a healthier work environment.