: Bellmann, B.; Muhle, H.; Pott, F.

Abstract
The carcinogenicity of mineral fibres depends on length and diameter, however, the exact relationships are not yet known. Additionally the biopersistence is an important factor: the carcinogenic effect in the intraperitoneal injection test of fibre types with a short half-time in the lung was weak or not detectable in the case of gypsum, wollastonite, glass ATF 3101, HCl-treated E-glass, and HCl leached chrysotile. After elimination from the tissue either by translocation or by disintegration a fibre can no longer act as a carcinogen. The minimum period of persistence could be seen as a kind of threshold value. It will be difficult to detect this threshold before knowing the mechanism of fibre carcinogenesis. However, a comparison of data on biopersistence of fibre samples in the lung with carcinogenicity data received after i.p. injection may give another approach for recognizing the threshold which is important for the regulation of fibres.