Hazardous factors of occupational diseases include physical noise, vibration, etc., chemical lead, mercury, dust, etc., and biological factors such as Bacillus anthracis and forest encephalitis virus. 1. Physical factors: such as noise, vibration; abnormal meteorological conditions, such as high temperature, high humidity, low temperature, high air pressure, low air pressure, etc.; ionizing radiation, such as ultraviolet rays, infrared rays, radio frequency, microwave, laser X-rays, radioisotopes, γ-rays produced by the instrument. 2. Chemical factors: such as lead, mercury, benzene, toluene, styrene and other poisons; production of styrene-butadiene rubber in the process of butadiene, styrene, high aromatic hydrocarbon oils, peroxide diisopropylbenzene and so on. Productive dust, such as petroleum coke dust in the process of oil refining; metal dust and cement dust in the process of catalyst production, as well as asbestos dust and coal dust. 3. Biological factors: e.g. Bacillus anthracis, forest encephalitis virus, brucellosis, etc. People in different occupations are exposed to different hazardous factors of occupational diseases and their severity varies, affecting people’s healthy life and physical fitness. Prompt medical attention is recommended in case of discomfort.