Police Lt Prapan Pitaksa said no one was injured in the fire in Rayong province at a facility belonging to IRPC Public Co. Ltd., which refines both petroleum and petrochemicals. He said the fire was put under control within 20 minutes.
Prapan said the fire was started by a gas leak which may have resulted from pipes that overheated or cracked from expansion.
Police said they could not immediately estimate the damage from the fire.
The area around Rayong, 180 kilometres southeast of Bangkok, hosts many of the country's heavy industries, which are serviced by port facilities on the Gulf of Thailand.