Massey Energy CEO Don Blankenship leaves a Senate Health and Human Services subcommittee hearing in Washington, D.C., on May 20, 2010, after answering questions about mine safety. Carolyn Kaster/AP hide caption
Upper Big Branch Mine disaster Upper Big Branch Mine disaster
Former Massey Energy Company Chairman and CEO Don Blankenship, seen in July 2010, has pleaded not guilty to conspiracy charges associated with the 2010 West Virginia mine explosion that killed 29 men. Jacquelyn Martin/AP hide caption
Mine helmets and painted crosses at the entrance to Massey Energy's Upper Big Branch coal mine, as a memorial to the 29 miners killed there. Jeff Gentner/AP hide caption
Oklahoma City Bombing: The Albert P. Murrah Federal Building shows the devastation caused by a fuel and fertilizer truck bomb on April 19, 1995. The blast killed 168 people and injured more than 500. Bob Daemmrich/AFP/Getty Images hide caption
In this 2010 photo, coal miner Terry Cooper, left, embraces his wife Michelle, daughter Tera and son Justin, during a vigil to honor the coal miners that were killed in Montcoal, W. Va. Mark Wilson/Getty Images hide caption
Mine helmets and painted crosses sat at the entrance to Massey Energy's Upper Big Branch coal mine on April 5, as a memorial to the 29 miners killed there one year earlier. Jeff Gentner/AP hide caption