A portion of the ceiling of the Grand Gaisano Mall in Toril, Davao City was destroyed Friday after the manhole cover of its septic tank was blown away.
Toril Police deployed a Explosive Ordinance Disposal (EOD) team, assuming initially that a bomb triggered the explosion.
Investigation later showed that the breather of the manhole was covered, causing fumes of methane gas to build up underneath and eventually cause the explosion.
“Sa pag-check ng EOD team natin, ‘yung fumes niya sa ilalim walang malabasan. ‘Yun ang nag-contribute din sa pagsabog,” said Chief Inspector Ronald Lao who investigated the case.
(Based on the EOD team’s assessment, the fumes underneath were blocked which contributed to the explosion.)