Firefighters belonging to the Tacubaya sector and workers dig for survivors after an explosion on Jan. 31, 2013, in Mexico City at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX. (Associated PRess)

Photo by: Guillermo Gutierrez

Firefighters belonging to the Tacubaya sector and workers dig for survivors after an explosion on Jan. 31, 2013, in Mexico City at an adjacent building to the executive tower of Mexico's state-owned oil company PEMEX. (Associated PRess)