Chemical exposures in research laboratories in a university.

Research laboratories in a university were investigated for air-borne levels of legally designated organic solvents and specified chemical substances. Repeated surveys in 2004-5 (four times in the two years) of about 720 laboratories (thus 2,874 laboratories in total) revealed that the solvent concentrations were in excess of the Administrative Control Levels only in a few laboratories (the conditions improved shortly after the identification) and none with regard to specified chemicals. Thus, working environments were in Control Class 1 in almost all (99.5%) laboratories examined. Such conditions were achieved primarily by extensive installation and use of local exhaust systems. The survey further revealed that types of chemicals used in research laboratories were extremely various (only poorly covered by the regulation) whereas the amounts of each chemical to be consumed were quite limited. For protection of health of researchers (including post- and under-graduate students) in laboratories, therefore, it appeared more appropriate to make personal exposure assessment rather than evaluation of levels of chemicals in air of research laboratories. Considering unique characteristics of research activity, it is important to educate each researcher to make his/her own efforts to protect his/her health, through supply of knowledge on toxicity of chemicals as well as that on proper use of protective equipments including exhaust chambers.

Lower vapor concentrations in solvent workplaces in larger-scale enterprises than in smaller-scale enterprises, and exceptions.

The aim of the present study was to investigate the relationship between environmental vapor concentrations in organic solvent workplaces and size of enterprises, and to examine if occupational hygiene conditions were better in larger-scale enterprises. For this purpose, a total of 3,567 solvent workplaces were surveyed for environmental solvent vapor concentrations in 1999 to 2002. The results were classified by the size of enterprises (taking the number of employees as an indicator) and by the type of solvent work. It was observed that the vapor concentration in a typical small-scale enterprise was approximately three times as high as that in the large-scale enterprise, although the administrative control levels were not exceeded in general. The proportion of testing and research work (with less use of organic solvents and thus low vapor concentrations) among all solvent workplaces was higher in large-scale enterprises than in small-scale enterprises. The vapor concentrations in this type of workplace did not differ however irrespective of the enterprise size. Further comparison in various types of solvent workplaces disclosed similar size-dependent difference in workplaces for degreasing, cleaning, wiping, printing, and surface coating. In painting and solvent-drying work, in contrast, there was no difference in environmental concentration regardless of the size of enterprises, possibly because environmental improvement of this type of workplaces was technically more difficult than others. Thus, it was concluded that large-scale enterprises generally had better control of work environments than small-scale enterprises, with possible exceptions of painting work and solvent-drying work.