General value An important goal of the study is to provide knowledge that can be important for workers who are exposed to particles and aerosols in the SiC-processing industry or other industries processing SiC and/or PEG. The study may also be relevant to workers in other industries with dusty environments given the possible "overload" mechanisms. The study could possibly also have the potential to provide additional knowledge about effects of exposure to similar particles e.g from air pollution. Because few former studies have used induced sputum in a prospective design, such studies are of particular interest.