The deadly price coal miners pay to supply us with energy

For decades, coal miners have been inhaling silica dust on the job. The extremely fine particles, generated when the quartz-rich limestone surrounding coal seams is cut, lodge in the lungs, obstructing respiration. According to a Frontline/NPR report, both the industry and the government understood the hazard for decades but did little to contain it. Howard Berkes of NPR joins John Yang.