This was the conclusion of the Philippine National Police (PNP), as well as explosives and demolitions experts from the U.S., Australia and Israel who helped the Philippine government investigate the Oct. 19 explosion at the Glorietta II mall.

“We are happy… that this cannot be attributed to terrorism because that would be a major development. It will affect our economy, our standing in the world community, our international investors,” Executive Secretary Eduardo Ermita said over the weekend.

“We are not happy about the explosion,” he said, “because people’s lives were lost, many were injured, but we just have to go by the result of the investigation.”

That investigation concluded that the explosion was an accident probably caused by a mixture of gases from a malfunctioning septic tank and a diesel tank in the basement of the mall. Vapor from the diesel tank could have mixed with methane from the septic tank causing the blast. The mall kept a large tanker of diesel for its generators as an alternative power supply.

Supporting the conclusionwas the absence of residue which would have been left over had a bomb or explosive device been used.

“It is good that this was not an act of terrorism,” said Ermita.
But the PNP has not totally ruled out the possibility that the explosion may have been triggered by a bomb. The PNP’s Bomb Data Center has not yet submitted its findings as its team returned to the site of the blast over the weekend to continue looking for bomb fragments and other residue.

Real estate giant Ayala Land, Inc. which owns and operates the mall did not agree with the conclusion arrived at by the PNP, which said “negligence” was the probable reason for the tragedy.

Ayala Land president Jaime Ayala said local and foreign experts hired by the company had debunked the PNP conclusion that the explosion was caused by negligence.

He said the company ruled out gas explosion as cause of the lunch hour incident. Damage to the mall has been estimated at P100 million and large parts of Glorietta II remain closed.

“We don’t think negligence is relevant with respect to this incident,” he said during a press conference Sunday. “It is highly unlikely that methane would be produced in the Glorietta II basement sump pits because the conditions for the production of methane in substantial quantities was not present,” Ayala added.

The Australian investigation team concluded that there was “no evidence to suggest that the explosion had been caused or initiated by an improvised explosive device,” according to PNP National Capital Region chief Geary Barias. The Israeli investigators also had the same conclusion.

They are waiting for the post-blast report from the U.S. Federal Bureau of Investigation to collate with all other findings before submitting a final report, Barias said.

But Ayala insisted the damage, which led to the partial closure of the mall, was too substantial to have been caused by gas build-up “We could not conclusively say whether or not there is a bomb crater,” he said, adding that their own experts had noted that the twisting of steel reinforcements was consistent with damage usually caused by a bomb.

Ayala spokesman Alfonso Reyes said their own technical crew had found no likely errors which could have caused the massive blast.

He said they would wait for the official report to be released this week before commenting. “We are hoping that the national police will release its report on the blast as soon as possible so we will be able to evaluate the findings and come up with a response,” Reyes said.

Shares of the listed company took a dive after the primary results of the investigation were released last week.