Because of the high incidence of aerodigestive malignancies in the inherited chromosomal instability disease Fanconi anaemia (FA), the universal presence of CIN in FA cells and complex cytogenetic defects in neoplastic FA cells, and the well-known biochemical role played by FA proteins in stabilising the genome (Bagby and Alter, 2006), we hypothesised that one or more of the chemicals in CSC might suppress the function of the FA pathway in normal individuals and destabilise the genome in exposed cells of the airway. This evidence concerns the gene FANCA and Friedreich ataxia.