An injured person is transported on a stretcher the headquarters of state oil giant Pemex in Mexico City January 31, 2013. An explosion rocked the Mexico City headquarters of Pemex on Thursday, killing one person, injuring more than 20 others and causing extensive damage to the building. A local emergency official said one person had died in the blast and 22 others were injured. Another four people were trapped inside the skyscraper, the official said. The blast, which media reports said was caused by machinery exploding, occurred in the basement, emergency officials said. REUTERS/Alejandro Dias (MEXICO - Tags: DISASTER ENERGY POLITICS TPX IMAGES OF THE DAY) Published: Úno. 1, 2013, 1:36 dop. | Foto: Reuters