[Relationship between asbestos exposure and malignant pleural mesothelioma: occurrence near the old Japanese naval shipyard].

Kure City, Hiroshima Prefecture, was the site of a Japanese naval shipyard before World War II, and commercial ships were built there after the War. Large amounts of asbestos were used in this area primarily for shipbuilding, from before the war to around 1975. Probably due to exposure to asbestos, the incidence of malignant pleural mesothelioma is high in this city. Of the 31 patients with this disease, 27 were men. Patients over 60 years of age constituted a high percentage of the total and 28 had a history of asbestos exposure: 12 in the Japanese naval shipyard and 12 in the commercial shipyards. The average period of asbestos exposure for these 28 patients was 20 years. Malignant pleural mesothelioma developed more than 40 years after the first exposure to asbestos. Many asbestos particles and fibers were detected in the lungs and tumors of these patients. Most of the asbestos fibers detected were crocidolites or amosites. Considering that the amount of asbestos used in Japanese has been higher than in any other country, the incidence of malignant pleural mesothelioma may be expected to increase in this country. Countermeasures are now advisable.