<P> Prolonged inhalation of asbestos fibers can cause serious and fatal illnesses including lung cancer , mesothelioma , and asbestosis ( a type of pneumoconiosis ) . Concern of asbestos - related illness in modern times began with the 20th century and escalated during the 1920s and 1930s . By the 1980s and 1990s , asbestos trade and use were heavily restricted , phased out , or banned outright in an increasing number of countries . </P>
when did asbestos become known to be harmful
began with the 20th century escalated during the 1920s and 1930s