Forensic police find ‘gas leak’ behind fatal bus fire

A probe by forensic police has concluded that a gas leak was the cause of the bus fire tragedy that claimed the lives of 20 students and three teachers on Tuesday.
Pol Lt Gen Trairong Phiewphan, commander of the Office of Police Forensic Science (OPFS), said on Thursday that an initial investigation found the gas leak occurred at the front of the bus.
However, it has not yet been determined what caused the sparks that ignited the flames, nor why the gas was leaking, he said.
Experts specialising in vehicle gas systems will be invited to provide further information.
An inspection by OPFS officers and experts also revealed that 11 tanks containing compressed natural gas (CNG) had been installed on the bus.
A House committee on transport invited officials from the Department of Land Transport (DLT) and the Automotive Engineering Bureau (AEB) on Thursday to explain the cause of the fire and discuss potential solutions.
Chirute Visalachitra, the DLT’s director-general, informed the committee that six of the eleven CNG tanks installed on the bus were registered, while the remaining tanks were not.
The inspection found that the gas leak originated from one of the unregistered tanks, which had not been checked by engineers, he said, adding that the police are working with the department to determine who is responsible.
“How did officials inspecting the bus fail to notice the excessive number of gas tanks?” Mr Jirut asked.
Cheep Nomsian, director of the AEB, told the House committee that the bus involved in the accident was a single-deck vehicle, not a double-decker, and that the emergency door at the rear was functional.
The inspection found no evidence of a front tyre explosion, as previously reported, he said, adding that the bus’s front-wheel axle was broken and showed signs of scraping against the road surface.
He also said that a fuel line, which carries gas from the tank to the engine, had come loose, causing the leak. Early reports from first responders indicated that the front left tyre had blown out, causing the wheel to catch fire. The driver then lost control, and the bus swerved into the median barrier. Flames rapidly engulfed the vehicle.
Following the incident, the DLT suspended the transport operation licence granted to Panisara Chinnaboot, the operator of the Sing Buri-based Chinnaboot Tour, Mr Jirut said.
The licence will be revoked if the investigation finds that negligence by the company caused the tragedy.
Mr Jirut also noted that the registration of Kanittha Chinnaboot as the company’s transport safety manager (TSM) has been revoked, and an investigation has been launched into Alternative Resource Engineering Co, which provides gas-fuelled vehicle inspection and testing services.
The licence of the bus driver, identified as Samarn Chanphut, 48, who surrendered to police on Tuesday night, has also been suspended. He faces losing his licence if found responsible.
There will be inspections of all 13,426 vehicles using CNG within 60 days.