Although concerned officials have not confirmed what caused the explosion, Sansern said the initial investigation found that a gas cylinder installed on the boat exploded and no explosive items were found. The incident took place near a pier at Wat Thep Leela.
Science and Technology Ministry deputy spokesman Worawarong Rakreungdet said the boat was powered by diesel and liquefied natural gas (LNG).
Officials suspected that the gas tank exploded. Witnesses saw smoke and smelled gas at the rear of the boat. However, the boat owner insisted the explosion occurred in the engine.
Deputy Transport Minister Omsin Chivapruek said he inspected the scene and found that the gas tank in the boat had leaked, causing a flame, but it did not explode.
The ministry has suspended all 30 gas-fuelled boats from operating on the Saen Saeb canal from a total of 72 boats until the cause of the incident is determined.
Chavalit Methayaprapat, the owner of Family Transport Co Ltd and operator of the boat, said the incident took place at about 6.45am while the boat was approaching Wat Thep Leela pier.
He said the explosion had nothing to do with the gas tank because the tank was still in a good condition. The boat did not capsize after the blast.
Chavalit said he had ordered that the company's 25 boats powered by LNG and diesel stop operating - leaving 47 diesel boats still running. He ordered the removal of gas systems from the 25 boats.
He said the gas systems were installed so the company did not have to increase fares. Eight years ago the price of petrol skyrocketed and the government promoted alternative energy
He said up to 40,000 commuters used the service each day on weekdays and 20,000 used it each day over the weekend.
Bangkok Governor MR Sukhumbhand Paribatra said of 60 injured people, 14 people needed to be hospitalised and four were in intensive care.
Winyu Angsunit, deputy managing director of Viriyah Insurance Plc, said the company initially estimated the damage bill at Bt1.1 million and would pay compensation to concerned parties with full coverage. Coverage was Bt100,000 for any person who died. The 60 injured would be paid Bt15,000 each, Winyu said.
The incident was unprecedented, he said, and the cause of the explosion initially found to be either an accident or the engine being too old. He said Viriyah Insurance would consider charging gas-powered boats higher premiums than for those that run on petrol.
An injured commuter, who declined to be named, said she was walking toward the rear of the boat near the engine when she saw smoke coming from the engine before the explosion. The engine is located in the middle of the boat.
Another commuter, who also declined to be named, said the boat was heading to Pratunam before it had mechanical problems. Before the explosion, the boat driver told commuters to get off at Wat Thep Leela and change to another boat, she said.