A Basic Framework of Working Environment for Occupational Health in Japan

This review deals with three aspects of occupational health practices in Japan, i.e., working environment control, work practice management and health care, with an emphasis upon working environment control. Control of chemical hazards and physical agents in working environment is of prime importance to prevent workers from health impairments due to the hazardous agents. The Japanese legislative system for control of hazardous agents in working environment is characterized by "workplace control", and it is different from "control of personal exposure based on exposure limits of hazardous substances". Hazardousness of working environment contaminated with a toxic substance is assessed by screening air sampling at workplace designated as Measurement A and by fixed point air sampling designated as Measurement B. Working environment was categorized as Control Class I, II or III with both geometric mean and geometric standard deviation of concentrations of the hazardous agent with reference to an "administrative control level". The nationwide survey of air concentrations of dust and lead at workplaces revealed that the present Japanese system of working environment control had been effective to reduce the number of the harmful workplaces evaluated as Control Class III, the worst category, in the decade of 1984-1993 throughout Japan.