Summary of article on cat litter dust:
Clay-based cat litters contain crystalline silica, the main component in sand, rock and mineral ores. A possible health threat from clay-based litters is posed by silica dust, which can be kicked up and breathed in by both cats and humans. Prolonged exposure to silica dust causes silicosis, a non-cancerous but sometimes fatal lung disease. Crystalline silica dust is also a suspected carcinogen, associated with bronchitis and tuberculosis. Although exposure to this dust is of great concern to those working in mines or on construction sites, the effects on cat owners exposed while cleaning their cat’s litter box are virtually unknown.