THE septic tank of Gaisano Grand Mall in Toril blew up on Friday night due to methane gas buildup.
Based on the initial investigation conducted by local authorities, around 6:30 p.m. on Friday, January 20, an explosion occurred outside the mall, alarming the public but brushed aside the possibility that it was a terrorist act.
Authorities conducting the investigation include Toril Police Station, Explosive Ordinance Disposal (EOD) unit of the Davao City Police Office (DCPO), Task Force Davao, and Bureau of Fire Protection (BFP) Davao.
According to the police, the blast may have been caused by methane, which comes from decaying organic wastes such as manure, wastewater sludge, municipal solid waste, including landfills or any other biodegradable feedstock.
Police who responded to the blast said witnesses reported that they heard a deafening blast that caused alarm among the shoppers.
The management immediately closed the establishment and secured the areas before the authorities arrived. Authorities declared it negative from any bomb-related cause.
No injuries were caused by the blast since it happened far away from the entrance. However, it caused the mall damages as the two concrete manhole covering the tank were expelled out from the pavement and hit the ceiling.
The management of the mall has started to fix the plumbing and sewerage systems to avoid similar incidents in the future.