Mexico Pemex Explosion

August 2, 2013 - 9:36 PM
FILE - In this Jan. 31, 2013 file photo, firefighters and workers dig for survivors after an explosion at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX, in Mexico City. Mexican authorities said in an Aug. 2, 2013 statement that gas could have built up for decades before an explosion caused three floors of the headquarters of the national oil company to collapse, killing 37 people. The statement said the explosion was ignited by either a mechanical or electrical spark. (AP Photo/Guillermo Gutierrez, File)