Global Asbestos Congress 2004

Prevention of Further Asbestos Exposure during Water Pipe Work and Survey on Health Effects of Asbestos Exposure among Active and Retired Employees

Hiroshi Watanabe
Japan Water Supply Workers' Union (ZENSUIDO), Japan

In approximately 10 years, from around 1957, during Japan's high economic growth period, the Waterworks Bureau of the Tokyo Metropolitan Government installed approximately 980 km of asbestos pipes in Tokyo's 23 wards, as well as approximately 2,500 km of municipal asbestos pipes in the Tama area. Removal work was more or less completed by around 1985, but there still remain a few dozens kilometers of asbestos pipes today, mainly in the Tama area. Apart from some directly managed undertakings, Bureau officials have been responsible for on-the-spot supervision and observation of work. Implementation of dust control measures has been compulsory since 1987; however, such measures are not always complied with in practice.

At the end of 2002, the Tokyo Water Supply Workers' Union (TOSUIRO) submitted a "Request for the Prevention of Further Asbestos Exposure and Survey on the Health Effects of Asbestos Exposure among Active and Retired Employees". In reply, the Water Bureau promised (i) to perform studies on how to perform removal work and implement optimum methods, and (ii) with regard to the "early detection of malignant mesothelioma due to asbestos exposure and health checkups," to conduct interviews/work experience surveys and direct that chest x-rays be taken in preliminary checkups, as well as that pulmonary function testing and CT scanning be used in detailed examinations.

In October 2003, the Bureau performed asbestos pipe cutting simulations. TOSUIRO requested that past work practices be reproduced as faithfully as possible during these simulations. In the case of some of the cutting methods, results revealed high values for dust concentration and other parameters, as well as the fact that dust would diffuse into the air immediately after the work was performed. However, the Bureau did not go as far as to estimate the effects of such asbestos exposure.

In future, investigators should be educated as part of efforts to establish a TOSUIRO survey system for rating actual work practices. Union members also require proper asbestos education as relatively few undergo health checkups.