Biopersistence of synthetic mineral fibers as a predictor of chronic inhalation toxicity in rats

In December 1997 the European Commission (EC) adopted Directive 97/69/EC (O.J. L 343/19 of 13 December 1997; European Commission, 1997) in which criteria were established for the classification and labeling of synthetic mineral fibers.

This directive was derived based upon an extensive program evaluating current scientific knowledge on fiber pathogenicity and its relationship to the biopersistence of long fibers. Within this context, the biopersistence of fibers longer than 20 µm was found to be a good predictor of the lung burden and early pathological changes in chronic inhalation studies with fibers as well as the tumor response in chronic intraperitoneal studies with fibers. These results were presented in a preliminary form in an internal report to the European Chemicals Bureau (1997b; ECB/TM/15(97)).

This article summarizes the report and expands the analysis that provided the scientific basis for the relationship of biopersistence to the chronic inhalation results.