The development and regulation of occupational exposure limits in Japan.

The Ministry of Health, Labor and Welfare, on an administrative basis, establishes and supervises the Administrative Concentration Level, which can be viewed as an Occupational Exposure Limit (OEL) legally binding employers to maintain a good working environment. The Japan Society for Occupational Health, on a scientific basis, establishes the Recommended OELs, which can be viewed as a reference value for preventing adverse health effects on individual workers. In the case of carcinogens, Reference Values are recommended instead of OELs, corresponding to lifetime excessive risk of 10(-3) and 10(-4). The former is based on monitoring of the ambient working environment (area monitoring) while the latter is based on the monitoring of the individual worker. The two OELs influence each other in the course of establishment.