Asbestos, collective name for various natural fibrous silicate minerals. Economically important were in particular chrysotile and crocidolite (blue asbestos). On account of their incombustibility, excellent insulating properties and high chemical resistance these materials were formerly used for asbestos cement, which contained approx. 70% asbestos for roofing materials and tubing, approx. 8% in the case of flooring materials, roughly 3% for protective clothing and roughly 5% for friction linings. Since asbestos causes respiratory tract cancer and asbestosis (dust in the lungs), the production and marketing of the chief products containing asbestos (fibre cement products for building purposes, friction linings and other products in which asbestos is poorly bonded) has been prohibited in Austria since 1990 (Asbestos Regulation). In the last few years, massive rehabilitation efforts have been made, in particular where spray asbestos had been used for insulation purposes.