Philippine mall blast caused by biogas, not bomb

MANILA, Jan. 10 (Xinhua) -- It was biogas build-up and not a bomb that caused last October's explosion at a Manila mall that killed 11 people and injured 100 others, said the Philippine National Police (PNP) on Thursday.

"We ruled out explosives as the cause of the explosion. Based on the findings, clearly bombing was not the cause of the explosion at (the basement of the mall) Glorietta 2," said Luizo Ticman, chief of the multi-agency task force responsible for the investigation at a press conference.

On the other hand, he said specimens recovered from ground zero and analyzed by the task force gave a "positive presence of hydrogen sulfide, a byproduct of biogas." Methane would comprise 65 percent of the whole biogas production, he added.

The investigator said the biogas was produced from waste. "These are human waste and vapor from diesel fuel," he said.

The explosion stemmed from methane and a sudden rise in temperature that caused the fuel to reach its flash point of 70 degrees, said the investigator.

"Liquid diesel is transformed into diesel vapor (at) 55 to 70 degrees," he said.

Ticman also cited testimonial evidence from team leader Elmer Giganto, who said there was a problem with the 7.5-horsepower submersible pump. He also said foreman Felix Paje testified smelling a foul odor and feeling hot at the basement because there was lack of ventilation.

"These things of course will contribute to the production of methane," he said.

Meanwhile, Ticman cited findings from the Philippine Bomb Data Center, National Bureau of Investigation and Makati Explosives and Ordnance Division that did not find traces of a bomb explosion.

A bombing would have left a crater, soot, explosive residues in the skin and clothing of victims, and components of a bomb or an improvised explosive device at the blast site, he said.

Earlier, Ayala Land Inc., the owner of the mall, said it is ready to face the outcome of the police investigation into the blast, even as it remained firm in contesting the findings made by the PNP that the blast was a gas explosion.

At least 15 people concerned will be charged in for reckless imprudence resulting to multiple homicides, serious physical injuries and damage to property.