The basic tasks of occupational health are the recognition, evaluation, prevention and control of harmful occupational working conditions. Here, working conditions refers to the working environment and all aspects of an employee’s terms and conditions of employment. Normally, it includes three parts: (1) the production process starting from raw materials through to the fi nished production. This process could be changed depending on the production technology, machinery and equipment, and kind of materials and processes; (2) the labour process , which includes labour organization, layout of production equipment, operators’ posture and form of labour; and (3) the working environment , which can be identifi ed as the place of work. The environment includes the indoor environment of a factory or offi ce building, or a car or truck and the surrounding atmospheric environment, as well as the natural environment of any outdoor work.