The accident happened on Lat Krabang Road. There were no casualties.
Four water trucks from the Bangkok Metropolitan Administration’s Fire and Rescue Department were used to control the LPG leak.
It took more than two hours before normality was returned, with the road closed to traffic during the operation.
The driver of the gas truck, Uthen Lohakarn, 30, said his vehicle was travelling in the second lane when he noticed the trailer truck making a turn.
“I could not apply the brake in time. So I swerved my vehicle to the third lane but still the two vehicles brushed,” he said. “The bang opened the valve on my truck.”
Uthen said he had driven the truck from Chachoengsao to deliver gas to petrol stations in Bangkok’s Prawet district.
The driver of the other truck, Boonchai Khumjaidee, said he was turning his vehicle when it was hit from behind, causing minor damage to it.