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.