There is a clear scientific consensus that asbestos in all its varieties (amphiboles or chrysotile) is a carcinogen in humans, even at low doses. Asbestos in its various mineral forms is a natural substance existing on all continents, with many remarkable chemical and physical properties. It has been known of since ancient times, and was used extensively in the 20th century for purposes as varied as protecting buildings and ships against fire, strengthening plastics, constructing sheeting and pipes (from asbestos cement), reinforcing road surfaces and making fireproof cord, gaskets and brake linings, and heat-protective clothing, to name just a few of its possible applications.
The general realisation that working with asbestos poses serious risks to health led more and more countries to adopt increasingly strict measures to protect workers from the mid-1970s onwards, and then to restrict and ban its use. Since the 1990s, repeated recommendations from health-related international organisations have aimed to replace asbestos with less dangerous technologies or substances. More and more states have decided to impose a total ban on all forms of asbestos, with some temporary exceptions for the few cases where substitution still presents some technical difficulties.