FILE - This Feb. 18, 2010, file photo shows a sample of tremolite in Libby, Mont. A long-delayed risk study released Monday, Dec. 8, 2014 for the Montana mining town where hundreds have died from asbestos exposure concludes that even a minuscule amount of the substance can lead to lung problems. The 328-page draft document will guide the remaining cleanup of asbestos dust from a W.R. Grace & Co. vermiculite mine outside Libby, a town of 2,600 people located about 50 miles south of the Canada border. The scenic mountain community has become synonymous with asbestos dangers since news reports 15 years ago first drew attention to the number of people dying from exposure. (AP Photo/Rick Bowmer, File)