A worker makes a cut in the side of a sandstone block at the Cleveland Quarries facility in Vermilion, Ohio, earlier this month. The legal limit on the amount of silica that workers can inhale was set decades ago. Ty Wright/Bloomberg via Getty Images hide caption

itoggle caption Ty Wright/Bloomberg via Getty Images

The Centers for Disease Control and Prevention says the accidental release of chlorine gas at a Tyson Food plant could have been prevented with better communication. April L Brown/AP hide caption

itoggle caption April L Brown/AP