Speedskaters practiced for the U.S. Single Distance Short Track Speedskating Championships in Kearns, Utah, last year. Rick Bowmer/AP hide caption

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A memorial at the entrance to Massey Energy's Upper Big Branch coal mine represents the 29 coal miners who were killed in an explosion in 2010. Jeff Gentner/AP hide caption

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A construction site in San Mateo, Calif., earlier this month. There were 738 deaths of construction workers in the U.S. during 2011, the most of any single industry. The fatality rate per workers was higher, when taken together, in agriculture, forestry, fishing and hunting Justin Sullivan/Getty Images hide caption

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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

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Jean A. Stevens conducts the morning session's closing prayer during the 183rd Annual General Conference of The Church of Jesus Christ of Latter-day Saints on Saturday, April 6, 2013, in Salt Lake City. Rick Bowmer/AP hide caption

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