Surface modification can affect the carcinogenicity of asbestos.

A sample of amosite asbestos was modified by effectively adding C8 and C18 hydrocarbon chains to the fibre surfaces. The altered fibres interacted less readily with cells in vitro and were less cytotoxic. In whole animals the number of mesotheliomas produced by the C8 material was the same as that with the parent material but the tumours occurred earlier. The C18 derivatized fibre was markedly less active in the production of tumours. This is the first report demonstrating that similar size fibres with differing surfaces have different pathogenic properties.