World

Photo: The Canadian Press. All rights reserved.

Firefighters belonging to the Tacubaya sector 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, Thursday Jan. 31. (AP Photo/Guillermo Gutierrez)

A blast that collapsed the lower floors of a building in the headquarters of Mexico's state-owned oil company, crushing at least 33 people beneath tons of rubble and injuring 121, is being looked at as an accident although all lines of investigation remain open, the head of Petroleos Mexicanos said Friday.

As hundreds of emergency workers dug through the rubble, the company's worst disaster in a decade was fueling debate about the state of Pemex, a vital source of government revenue that is suffering from decades of underinvestment and has been hit by a recent series of accidents that have tarnished its otherwise improving safety record.

Until now, virtually all the accidents had hit its petroleum infrastructure, not its office buildings.

" It seems like, from what one can observe, from what the experts are seeing, that it was an accident",'' Pemex Director-General Emilio Lozoya told the Televisa network. "However no line of investigation will be discounted."

Mexican President Enrique Pena Nieto has pledged to open the oil behemoth to more private and foreign investment, setting off warnings among leftists about the privatization of an enterprise seen as one of the pillars of the Mexican state. Pena Nieto has provided few details of the reform he will propose but denies any plan to privatize Pemex.