Case Reports and Analyses of Tonoko

We found three cases of pneumoconiosis among those workers who had been dealing with tonoko (a mineral powder) for more than ten years at a shop making wooden furniture in Sendai, Japan. In the factory the workers were exposed to tonoko dust and had been inhaling it for a long time. Until now, this disease has not been found in employees of furniture factories; and, furthermore, tonoko has not been regarded as a harmful material. Tonoko is a very fine mineral powder used T onoko has not been recognized as a harmful