Pneumoconioses typically result from breathing in high concentrations of these dust particles over many years, although disease can occur and progress rapidly after short periods of intense exposure.
If the lungs become overwhelmed by high concentrations of dust or are damaged by the long-term inhalation of dust particles, some of the dust remains in the lungs. In simple pneumoconiosis, the dust that isn't cleared by the lung's natural defenses causes an inflammatory reaction that results in the formation of small nodules or scars.
Progressive Massive Fibrosis
More complicated, severe and less frequent forms of pneumoconiosis from silica or coal mine dust inhalation are known as Progressive Massive Fibrosis (PMF). In PMF, the scarring progresses (becoming widespread), changes the structure of the lung, and destroys airways and blood vessels, resulting in an increasing loss of lung function, disability and often death.