Crystalline silica (quartz) is a. ubiquitous mineral dust found worldwide. Occupational exposure to free silica occurs in. several large categories of industry. The pathogenesis of silicosis begins with the inhalation of free crystalline silica particles that. have favorable characteristics for deposition in the alveolar spaces. Following inhalation, the particles interact with epithelial cells and pulmonary macrophages to initiate injury and cause fibrosis (Cosio and Majo, 2002).