silicosis

Silicosis is a fibrotic lung disease caused by inhaling fine dust of crystalline silica — the main mineral in quartz, found in rock, sand, concrete and stone. Think of cutting or grinding stone all day: the cloud of dust it raises contains microscopic, glass-sharp particles that the lungs cannot dissolve away.

When these silica particles reach the small airways and alveoli, scavenger cells called macrophages engulf them, but the silica is toxic and destroys the very cells trying to remove it. The dying cells release signals that draw in more immune cells and lay down collagen, forming small scarred nodules. Over years these nodules grow and coalesce, stiffening the lungs and, in severe cases, forming large fibrotic masses (progressive massive fibrosis).

Silicosis comes in forms reflecting exposure intensity: chronic silicosis after many years of moderate dust, accelerated silicosis over a few years, and rare acute silicosis from intense exposure. Symptoms are breathlessness and cough; there is no cure, and management is supportive. Importantly, silicosis greatly raises the risk of tuberculosis, and silica exposure also increases lung cancer risk. Modern outbreaks among workers cutting engineered (artificial) stone countertops show this is far from a disease of the past.