Coalinga Chrysotile: A Short-Fibre,Amphibole-Free,Chrysotile: Part VI - Additional Evidence for Lack of Fibrogenicity

Abstract

This report describes additional unpublished data that support the notion that Coalinga chrysotile is not fibrogenic. These data are from the same long-term, NTP-NIEHS, chronic chrysotile inhalation study that served as the basis for our earlier publications which concluded that Coalinga chrysotile was not fibrogenic due to its lack of biopersistence. Wagner-scored 12 and 24 month interim sacrifice data from the NTP-NIEHS investigation and an unpublished data set from the comparison MRC study both previously unreported, were recently found in the author’s files. The histology slides and attendant data should have been amongst the materials archived at the NTP but were not present at the time the author reviewed those files in 1995 and 1996. Review of these new materials showed that Coalinga chrysotile did not produce fibrosis either at 12 or 24 months in contrast to the two Canadian preparations which were both fibrogenic even at this early stage of the study. These new data and related testimony greatly strengthen our earlier conclusions and serve to refute earlier apparently contradictory reports. International and Governmental Reports support the conclusion reached in our papers that Coalinga chrysotile is not pathogenic. In fact, the only scientists to criticise our conclusions have been in litigation against Union Carbide.