The explosion on the Khlong Saen Saep commuter boat which injured 67 passengers earlier this month may have been caused by an accumulation of gas ignited by the heat of the vessel's exhaust pipe, a Transport Ministry source said.
A Marine Department committee has finished its probe into the cause of the blast and will forward the findings to the Transport Ministry, the source said.
The committee is headed by Kritpetch Chaichuay, director of the Marine Safety and Environment Bureau.
The source said the findings reveal the gas may have been ignited, causing the blast.
The boat was equipped with a dual-fuel liquefied natural gas (LNG) and diesel engine. The source said LNG was released from the gas tank through two security valves.
A pipe was connected to one security valve to release the gas into the air, but the other valve had no such connection, resulting in the gas drifting into the vessel's engine.
There was also the possibility that a large quantity of LNG released from the valve accumulated in the airtight engine compartment and was ignited by the exhaust pipe's heat, the source said.
The explosion took place while the gas-powered boat, carrying about 80 passengers, was docking at Wat Thep Leela pier early on March 5.