Abstract
Tonoko, which is broadly used in processing wooden furnitures in Japan, has not been accepted as a causal substance of pneumoconiosis. Three cases of pneumoconiosis were found among four workers who have been engaged in wooden furniture painting and have dealt with tonoko daily for more than ten years. The atmosphere in their working room is always dusty and it is supposed that the main content of the dust is tonoko. Analysis revealed that tonoko was a soil substance which contained about 50% quartz. The results support the assumption that their disease may be referable to tonoko inhalation.
