Shift to non-aromatic solvents in solvent workplaces in Japan.

OBJECTIVES: The present analyses were initiated to elucidate changes in types of prevalently used organic solvents in various solvent workplaces in Japan during the past 30 years. METHODS: Five publications on industrial solvent use were employed as databases, which were supplemented by solvent workplace surveys in 2010-2012; the surveys were conducted following regulation-stipulated procedures. In practice, data on 500-600 unit workplaces/year were available; the data were classified by types of solvent work according to the regulation. RESULTS: The use of aromatic solvents (typically toluene) has been gradually replaced in a recent few years with methyl alcohol and isopropyl alcohol in surface coating workplaces, whereas toluene has been essentially most prevalent in printing and painting workplaces. In cleaning workplaces, the use of chlorinated hydrocarbon solvents was almost terminated in the years before 2000. CONCLUSIONS: The present study may be the first report to note that the prevalence of toluene use has been decreasing in surface coating workplaces to be replaced by alcohols, although toluene has been most prevalent in printing and painting workplaces. In cleaning workplaces, there was a substantial reduction in the use of chlorinated hydrocarbon solvents.

Use of organic solvents in large research institutions in Japan.

OBJECTIVES: Laboratories in research institutions use organic solvents in research and development. Nevertheless, the types of solvents in use have been seldom reported. This study was initiated to elucidate types of organic solvents used in large research institutions in Japan, with a focus on possible different use among research fields. METHODS: In 2010-2011, 4517 laboratories in seven large research institutions were visited. In accordance with legal stipulations, air in each laboratory was collected in polyvinyl fluoride bags and analyzed by direct injection into a gas-chromatograph for 47 types of organic solvents. In evaluation, the laboratories were grouped by 5 research fields, i.e., agriculture, biology, medicine, natural science, and technology and engineering. RESULTS: Types of organic solvents commonly used in research activities were not diverse. Those commonly used were chloroform and 1,2-dichloroethane out of 7 Group 1 organic solvents (with high toxicities); 6 organic solvents, i.e., acetone and methyl alcohol in general, ethyl acetate, hexane and toluene in technology and engineering laboratories; and xylenes in medical fields out of 40 Group 2 organic solvents (with relatively low toxicities). Judging from solvent vapor concentrations, work environments in more than 99 % of laboratories were considered adequate. Nevertheless, use of chloroform in high-performance liquid chromatography (HPLC) resulted in inadequate environments in 30 laboratories (0.7 %). CONCLUSIONS: Organic solvents commonly used were not very diverse. Work environments in research laboratories were generally good, but the environment with use of chloroform in HPLC analysis remained yet to be improved.

Organic solvent use in enterprises in Japan.

This study was initiated to elucidate possible changes in types of organic solvents (to be called solvents in short) used in enterprises in Japan through comparison of current solvent types with historical data since 1983. To investigate current situation in solvent use in enterprises, surveys were conducted during one year of 2009 to 2010. In total, workroom air samples in 1,497 unit workplaces with solvent use were analyzed in accordance with regulatory requirements. Typical use pattern of solvents was as mixtures, accounting for >70% of cases. Adhesives spreading (followed by adhesion) was relatively common in small-scale enterprises, whereas printing and painting work was more common in middle-scale ones, and solvent use for testing and research purpose was basically in large-scaled enterprises. Through-out printing, painting, surface coating and adhesive application, toluene was most common (being detected in 49 to 82% of workplaces depending on work types), whereas isopropyl alcohol was most common (49%) in degreasing, cleaning and wiping workplaces. Other commonly used solvents were methyl alcohol, ethyl acetate and acetone (33 to 37%). Comparison with historical data in Japan and literature-retrieved data outside of Japan all agreed with the observation that toluene is the most commonly used solvent. Application of trichloroethylene and 1,1,1-trichloroethane, once common in 1980s, has ceased to exist in recent years.

Organic solvent use in research institutions in Japan.

In 2008-2009, types of organic solvents used and air-borne vapor concentrations were surveyed in 1909 laboratories in four large research institutions in accordance with current regulations. The results were classified into 5 groups in terms of research fields (agriculture, biology, medicine, natural science, and technology and engineering) and evaluated after the regulatory rules. Laboratory air analyses by gas chromatography identified 5 and 20 solvents out of 7 Group 1 solvents and 40 Group 2 solvents, respectively; 10 solvents were used in more than 10% of the laboratories in each of the 5 research fields. The use of unmixed single solvent appeared to be unique in research laboratories in contrast to use of solvent mixtures in industrial facilities for production. Laboratories of technology and engineering fields used more various organic solvents more frequently, whereas use of xylenes appeared to be more specific to laboratories of bio-medical fields. Among the commonly used solvents, chloroform was the leading solvent to induce poorer results in regulatory classification (i.e., Class 3 in Administrative Control Classes) typically when applied in high pressure liquid chromatography which was too voluminous to be accommodated in a local exhaustion chamber.

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.

Relation of average and highest solvent vapor concentrations in workplaces in small to medium enterprises and large enterprises.

The present study was initiated to examine the relationship between the workplace concentrations and the estimated highest concentrations in solvent workplaces (SWPs), with special references to enterprise size and types of solvent work. Results of survey conducted in 1010 SWPs in 156 enterprises were taken as a database. Workplace air was sampled at > or = 5 crosses in each SWP following a grid sampling strategy. An additional air was grab-sampled at the site where the worker's exposure was estimated to be highest (estimated highest concentration or EHC). The samples were analyzed for 47 solvents designated by regulation, and solvent concentrations in each sample were summed up by use of additiveness formula. From the workplace concentrations at > or = 5 points, geometric mean and geometric standard deviations were calculated as the representative workplace concentration (RWC) and the indicator of variation in workplace concentration (VWC). Comparison between RWC and EHC in the total of 1010 SWPs showed that EHC was 1.2 (in large enterprises with>300 employees) to 1.7 times [in small to medium (SM) enterprises with < or = 300 employees] greater than RWC. When SWPs were classified into SM enterprises and large enterprises, both RWC and EHC were significantly higher in SM enterprises than in large enterprises. Further comparison by types of solvent work showed that the difference was more marked in printing, surface coating and degreasing/cleaning/wiping SWPs, whereas it was less remarkable in painting SWPs and essentially nil in testing/research laboratories. In conclusion, the present observation as discussed in reference to previous publications suggests that RWC, EHC and the ratio of EHC/WRC varies substantially among different types of solvent work as well as enterprise size, and are typically higher in printing SWPs in SM enterprises.

Field survey on types of organic solvents used in enterprises of various sizes.

OBJECTIVE: To examine (1) common types of organic solvent work and prevalent types of solvent used, and (2) possible association of high solvent concentration with types of solvent work and with enterprise size. METHODS: The present survey was conducted in Kyoto, Japan, in April 2004 to March 2005. Air samples were collected in 1,010 solvent workplaces (SWPs) (>or=5 samples/SWP) in 156 enterprises of various sizes, and analyzed for 47 legally designated organic solvents by flame-ionization detector-equipped gas-liquid chromatography. The geometric mean value of the concentrations (after summation by use of the additiveness formula) in the >or=5 samples were taken as a representative value for the SWP. Solvent works were classified into 11 categories according to the Japanese regulation. Enterprises were classified in terms of number of employees. RESULTS: Degreasing (including cleaning and wiping) was the most common type of solvent work, followed by painting and printing, and toluene was the most often detected solvent (i.e., in 42% of the 1,010 SWPs). Further observation by types of solvent work disclosed that toluene was most common in printing (61%), painting (78%), and adhesive spreading/adhesion SWPs (47%), whereas isopropyl alcohol was the leading solvent in cases of surface coating (51%) and degreasing/cleaning/wiping SWPs (42%). Use of methyl alcohol was also high (36% of all cases). In contrast, use of hexane in adhesives was limited (12%). There was a reverse size-dependency in solvent concentrations in air of SWPs, being five times higher in enterprises with or=501 employees. Among SWPs, concentrations tended to be high in printing workplaces especially in small enterprises. In contrast, the levels were much lower in testing and research laboratories irrespective of enterprise size. Comparison with the results in a previous survey in 1996 (Ukai et al. 1997) showed that use of toluene and xylenes was reduced and use of isopropyl alcohol and methyl alcohol was increased. The need of continuous updating of the target analyte list was stressed in relation to the limitation of the present study. CONCLUSIONS: Solvent levels were about five times higher in small enterprises as compared with the levels in large enterprises. There was a gradual shift in solvent use from aromatics to other solvents, typically alcohols. The use of hexane in adhesives was reduced. Solvent levels were relatively high in solvent-drying and printing workplaces and low in degreasing/cleaning/wiping workplaces and testing/research laboratories.