Silica has long been known to cause silicosis, a progressive, irreversible, but preventable lung disease that kills people. The National Institute for Occupational Safety and Health (NIOSH) reported that in 2007, 120 workers died from silicosis; 180-360 new cases of the disease are reported each year. Recent evidence shows that silica exposure also causes lung cancer. OSHA estimates that a lower allowable limit on silica in the workplace would prevent 60 deaths each year.