Survey on the health effects of chronic exposure to dioxins and its accumulation on workers of a municipal solid waste incinerator, rural part of Osaka Prefecture, and the results of extended survey afterwards.

In September 1998 the Ministry of Health and Welfare announced that high concentrations of dioxins were detected in the samples of soil near the incinerator and ash, drainage, sludge and others remained in the furnace and air pollution control devices of municipal solid waste incinerator (MSWI) in rural part of Osaka Prefecture. According to the results the Ministry of Labor immediately organized the "Research and investigation committee on the dioxin problem of Toyono-gun Clean Center" under Japan Industrial Safety and Health Association to investigate the health effects of chronic exposure to dioxins and its accumulation on workers of the incinerator plant. The investigation was carried out in Sept 1998 and from the results, the committee concluded that the concentrations of dioxin among the blood of the workers who had engaged in maintenance of the furnace, the electric dust collector, and the wet scrubber of the incinerator were higher compared with those of residents in surrounding areas. However, there were no signs or findings correlating to blood level of dioxns, and the level was not high enough to induce sufficient health effects from the review of published papers. According to the results of this survey the committee understood that the follow-up study of blood dioxins level of group III and IV workers was inevitable and concerned about the other MSWI workers in Japan who might also be exposed to similar level of dioxins. The Ministry of Labor decided to expand the survey to other MSWI workers in Japan as 3-year project from 1999. The summarized report on the project is appended in this paper.