Dye-manufacturing workers and bladder cancer in South Korea

Abstract

Dear Editor, Manufacturing beta-naphthylamine, which is considered to be a strong carcinogen, was abandoned in European countries from the 1930s to 1950s. Manufacturing benzidine was sustained with preventive measures against health hazards but because tumors continuously occurred despite these eVorts it also was abandoned in the United Kingdom in 1956 (Wallace 1988), in Germany in 1971 (Golka et al 2004), and in the United States in 1973 (Walker and Gerber 1981). The history of dye industry in Korea is closely related with that in Japan. Japanese government banned the manufacture and use of beta-naphthylamine, benzidine, 4-aminobiphenyl and 4-nitrobiphenyl, which turned out to be carcinogenic based on the epidemiological study showing the high prevalence of bladder cancer in workers or ex-workers exposed to aromatic nitrogen compounds (Shinka et al. 1991). Japanese government was forced to shut down dye manufacturing in 1972. On the other hand, Korean dye manufacturers by implementing these technologies from Japan have expanded remarkably since then. There was a lot of controversy over its suspension of production of benzidine or benzidine-based dyes since 1980, but the decision was deferred due to the importance of the dye industry. In 1990s, there were one factory manufacturing benzidine illegally and also manufacturing benzidine chlorides and eight factories using benzidine chlorides in Korea. However, Wnally even manufacturing benzidine-based dyes and benzidine dichlorides were legally prohibited in 2000 in Korea. The latent period of bladder cancer due to benzidine is generally known to be 20 years or more, though it varies with the exposure level and duration. Considering that the peak use of benzidine was in 1980s in Korea, the outbreak of bladder cancer due to benzidine is highly expected in early 2000s. Hence, the authors intend to examine bladder cancer incidence of those who were exposed to benzidine or benzidine chlorides. The subjects in our study were factories and its workers that manufactured benzidine or benzidinebased dyes in Korea (see Table 1).