Gas leak caused tragic Thailand school bus fire—police

Thailand police found that the tragic school bus fire that killed 20 students and three teachers was caused by a gas leak.

The Bangkok Post reported that Trairong Phiewphan, commander of the Office of Police Forensic Science (OPFS), said the gas leak happened at the front of the bus.

Still, it wasn't determined what caused the sparks that ignited the flames and why the gas was leaking.

OPFS experts also found that 11 tanks containing compressed natural gas had been installed on the bus.

Jirut Wisanjit, director general of the Department of Land Transport (DLT), said six of the 11 tanks were registered and the remaining tanks were not.

The leak originated from one of the unregistered tanks, which engineers weren't able to check.

Cheep Nomsian, director of the Automotive Engineering Bureau, said the bus was single-deck and its emergency door was functional.

Nomsian noted that there was no evidence of a front tire explosion and the bus' front-wheel shaft was broken and showed signs of scraping against the road surface. He added that a fuel line, which carries gas from the tank to the engine, had come loose, causing the leak.

Earlier, the driver Saman Chanput told the police he was driving normally until the bus lost balance at its front right tire, hit another car, and scraped a concrete highway barrier. That caused sparks that triggered the fire.

He ran to grab a fire extinguisher from another bus that was part of the same trip but couldn't put out the fire, prompting him to run away out of panic.

Chanput surrendered to authorities several hours after the fire. He was charged with reckless driving causing deaths and injuries, failing to stop to help others, and failing to report the accident. His license was suspended and could be revoked if found responsible.

The DLT suspended the transport operation license of Panisara Chinnaboot, the operator of the bus company Chinnaboot Tour. It also revoked the registration of Kanittha Chinnaboot as the company's transport safety manager, according to The Bangkok Times.

Owner Songwit Chinnaboot earlier said the bus was inspected for safety twice a year as required and that the gas cylinders had passed the safety standards. Songwit said the victims' families would be compensated.

Alternative Resource Engineering Co., which provides gas-fueled vehicle inspection and testing services, is also under investigation.

The bus, which was carrying six teachers and 39 students, was traveling from Uthai Thani province, about 300 kilometers (186 miles) north of the capital Bangkok, for a school trip in Ayutthaya and Nonthaburi provinces on Oct. 1 when it caught fire.

Sixteen students and three teachers were sent to the hospital due to the incident.