Highly toxic blue asbestos has been found in the lungs of two patients suffering from mesothelioma–which is allegedly caused by the material–who lived near Kubota Corp.’s former Kanzaki plant in Amagasaki, Hyogo Prefecture. The plant, run by the major machinery manufacturer, used blue asbestos from 1957 to 1975. The two patients lived near the plant during the same period.

The findings were made by Yuji Natori, a doctor and director of the Mesothelioma–Pneumoconiosis–Asbestos Center in Tokyo, and others who examined the lungs of six patients aged 52 to 66, including those who were deceased. All six of the patients lived near the factory when it used blue asbestos in the manufacture of water pipes.


Most of the asbestos discovered by the researchers in the lung tissue samples of the two patients was blue asbestos, which is believed to be the most carcinogenic variety. Its production and use were banned in 1995 prior to the banning of chrysotile, another type of asbestos. The researchers found 112 to 677 strands of asbestos per gram in lung tissue samples, much higher than the acceptable average of 35 strands.