梅日新同志: 来信问及职业病防冶的“三级预防”原则是什么的问题。作业环境中致病因素,包括生物、化学、物理和心理等方面的因素,统称为职业危害因素。这些因素是否可致病损,还取决于其他两个因素,即个体状况和作用条件。在职业致病过程中,职业危害因素是病因,而作用条件,如危害因素的接触量、接触频率、暴露时间等,则是促使病因诱发病损的前提。无疑,去除了病因或控制了作用条件,就能收到预防职业病损的效果 Comrade Mei Rixin: I asked what is the “tertiary prevention” principle of occupational disease prevention and cure. Pathogenic factors in the operating environment, including biological, chemical, physical and psychological factors, collectively referred to as occupational hazards. Whether these factors can cause lesions, but also on the other two factors, that is, individual conditions and the conditions of action. Occupational hazards in the process, the occupational risk factors is the cause, and the role of conditions, such as exposure to hazardous factors, exposure frequency, exposure time, is to promote disease-induced preconditions. Undoubtedly, the effect of preventing occupational diseases can be received by removing the cause or controlling the action condition