POSTED: Tuesday, February 5, 2013 - 9:00am
UPDATED: Tuesday, February 5, 2013 - 9:04am
NBC News — Last week's deadly blast at Pemex headquarters in Mexico City was caused by a build of up gas, according to the Mexican government. During a news conference monday night, Mexico Attorney General Jesus Murillo Karam (seen above) said there were no traces of explosives at the scene of the blast. Thirty seven people died with 29 people still hospitalized with injuries related to thursday's explosion. Karam said most of the fatalities happened when the blast caused part of the structure to collapse.
He said gas may have leaked from containers in a storage facility connected to where the explosion took place near a tunnel. Or, he said, it could have leaked from an aging pipeline that passed through the building. Thursday's explosion prompted speculation the incident could have been an act of sabotage. In the days immediately after the tragedy, government officials have been nearly silent about a possible cause.