The oncogenic effect of fibrous dust. Animal experiments and their relationship with human carcinogenesis

: The results after intraperitoneal injection of fibrous and granular dusts in rats suggest, that the fibrous shape of asbestos is the cause of its cancerogenicity. Fibrous dusts other than asbestos (for example glass fibers) may induce tumours, when their diameters are like that of asbestos and the fibres are invariable in tissue. It is supposed, that a fibre with a diameter less than 1 mum and a length greater than 3 mum has a cancerogenic effect. The interpretation of the experimental results considering the cancerogenesis in humans is discussed, especially concerning the effect of fibrous glass.