Investigations

Clay Mullins (left), brother of mine disaster victim Rex Mullins, listens as Upper Big Branch miner Stanley "Goose" Stewart tells the House Education and Labor Committee that the mine "was a ticking time bomb" because of problems with ventilation and explosive methane and coal dust. Jon C. Hancock/AP hide caption

A Mexican soldier stands guard as a haul of marijuana and cocaine are incinerated in the background in November 2009. Fighting among the drug cartels — and between government forces and the cartels — has cost nearly 24,000 Mexican lives since late 2006. Jesus Alcazar/AFP/Getty Images hide caption

The Santa Fe bridge (shown in February 2010) links the Mexican city of Ciudad Juarez (bottom) with the U.S. city of El Paso in Texas. American law enforcement officials say they are worried that violence from newly Sinaloa-controlled areas of Ciudad Juarez will spill over into the U.S. Alexandre Meneghini/AP hide caption

Mine workers stand at the entrance of the Upper Big Branch coal mine on April 9, a few days after an explosion killed 29 men. Matt Sullivan/Getty Images hide caption

Oil leaks into the Gulf of Mexico from the end of the pipe that was supposed to pump oil from the sea floor before the Deepwater Horizon oil rig exploded and sunk last month. BP PLC/AP hide caption

Choy, here with his wife, Monica, says he is angry that the waiver he signed relinquishes the oil company from responsibility, when responsibility on the oil rig was what the company stressed to its workers. Ben Sklar for NPR hide caption

Christopher Choy is haunted by the sound of explosions and the guilt of leaving men behind. Ben Sklar for NPR hide caption