[Toxicity of formaldehyde exposure and the details of its control measures].

The indoor air quality guideline (0.08 ppm) for formaldehyde was set in 1997. Afterwards, the occupational indoor air quality guideline for workplace where formaldehyde was manufactured or treated (the specific workplace handling formaldehyde) was set at the value of 0.25 ppm. In addition, the Labor Standards Bureau of the Ministry of Health, Labor and Welfare, has done a risk-based evaluation by using risk assessment analysis, in order to prevent the adverse effect of certain chemical materials on workers' health. In the case of formaldehyde, the primary evaluation value was assumed to be 0.033 ppm that corresponded in carcinogenic risk level 10(-4) with adjusted level for workers. The secondary evaluation value was assumed to be 0.3 ppm which was the Threshold Limit Value-Ceiling (TLV-C) recommended by the American Conference of Governmental Industrial Hygienists. Working environment measurement ("A" measurement methods) and/or individual exposure monitoring of formaldehyde at 22 workshops, where workers were potentially exposed to formaldehyde, were performed. The working environmental level in 3 workshops and the individual exposure level of 14 workers exceeded the secondary evaluation value (0.3 ppm). The rule for preventing the impairment of workers' health caused by the specified chemical substances was then revised so that formaldehyde was controlled more strictly and was reclassified from the third group to the second group of specified chemical substances. In addition, the administrative level of formaldehyde was set to 0.1 ppm, because of around a half of TLV-C value. Medical students have exposed to about 0.55 ppm in average formaldehyde during anatomy practice in the investigation of Japanese Association of Anatomists, though the gross anatomy practice room does not receive the restriction of the administrative level of formaldehyde. It is preferable that the exposure concentration of formaldehyde to the medical students is 0.1 ppm or less because formaldehyde is an irritant gas and a sensitizing potential, and is also a human carcinogen.