Fibrosis and scarring of the lungs due to the chronic (long-term) occupational inhalation of dusts such as coal, silica or asbestos. Silicosis is the most common form of pneumoconiosis and is caused by inaling free silica or crystalline silica (SiO2). Asbestiosis is a form of pneumoconiosis caused by inhalation of asbestos fibers. There are additional forms of pneumoconiosis that affect coal miners, welders, hard mineral dusts, talc, kaolin and more. See: The first link under Further Reading below. MSDS Relevance: MSDS's will warn of pneumoconiosis if the material is known to cause this kind of damage. Pneumoconiosis is a serious hazard at locations where dust is produced. Examples include coal mines, quarries and foundries. Breathing dust day after day is not normal and can result in permanent lung damage. Always take care to minimize the formation of dusts in the first place and use adequate personal protective equipment (PPE) such as dust masks or respirators in the presence of such materials. Keep in mind that the lung damage caused by inhalation of dusts may initially not cause any symptoms, even though damage has been done. If you wait until symptoms appear before taking appropriate precautions, the damage may be irreversible. See also: Emphysema, Fibrosis