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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Will Piper and Annette Pacas visit the grave of Annette's son, Alex, at Oak Hill Cemetery in Mount Carroll, Ill. Piper says he hopes to raise money to replace the makeshift, plastic marker with a permanent gravestone. John W. Poole/NPR hide caption

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