0 Official: Gas leak caused Mexico oil company blast

A gas buildup under a building in the headquarters of the Mexico's state oil company caused a blast that killed 37 people and wounded dozens, the attorney-general said Monday, ending days of near-total silence by authorities about the petroleum giant's worst disaster in more than a decade. Attorney-General Jesus Murillo Karam said an investigation by Mexican, Spanish, U.S. and British experts found no evidence of explosives in the blast that collapsed several lower floors of the Petroleos Mexicanos administrative building on Thursday afternoon. 

He said investigators believed that an electrical spark or other source of heat had detonated the gas. With the exception of three victims found in the area of the explosion, none of those killed had the burn marks or damaged ear drums that are typical evidence of a bombing, he said. There was also no sign of a crater or fracturing of the building's steel beams, also common signs of the detonation of an explosive device. Murillo said officials had yet to discover the source of what initial evidence indicated to be methane gas that leaked from a duct or tunnel or built up from the sewer system. 

He described the blast as a "diffuse" explosion whose blast moved slowly and horizontally, typical of the detonation of a cloud of gas, rather than an explosion that would have emanated from a relatively compact source like a bomb. He said laboratory tests had turned up "zero" evidence of any explosive. "We've been able to determine that the explosion was caused by an accumulation of gas in the basement of the building," he said. 

"This explosion, at its peak, generated an effect on the structures of the floors of the building, first pushing them up and then causing them to fall, and that was the primary cause of deaths in the building." The announcement late Monday ended days of a near-total lack of information about the potential cause of the incident. The lack of information spawned a torrent of complaints about government secrecy and speculation about the cause of the blast, most focusing on the possibility that it was intentional.

source : the jakarta post