Thailand, Bangkok

Officials in Thailand have verified the cause of Sunday's explosion of a compressed natural gas (CNG) cylinder on a truck at a PTT petrol station as an illegally installed gas fuel system. The explosion occurred during refilling. An inspection by the Energy Business Department and PTT found that all seven cylinders installed in the natural gas vehicle (NGV) were in poor condition. The cylinder walls were found to be thinner than specifications, with less capacity to handle the high pressures used for NGV systems. Fibreglass coverings typically used with NGV tanks to boost durability were also ripped and in bad condition.

Energy Business Department director-general Metta Bunterngsuk is quoted as saying the gas cylinders (type II) had been imported by a recycling plant as scrap metal. But instead of being recycled, the cylinders were patched up and resold as part of an NGV kit, despite not meeting official safety standards. Around 21 authorised garages have been given licences by PTT and the Land Transport Department to modify and install NGV conversion equipment. However, Confederation of Thai Truckers secretary-general Thongyu Yongkhan apparently said many truckers had turned to illegal garages that charged tens of thousands of baht less for the modification.

  The blast injured seven people (mainly harm to ears) and caused extensive damage to property. According to The Bangkok Post all motorists seeking to refill with CNG, which is sold locally as natural gas for vehicles (NGV) by the only supplier PTT, will have to show PTT cards certifying the safety of their fuel systems.

Thailand currently has approximately 66,000 registered CNG-powered vehicles, mostly taxi fleets operating in Bangkok. PTT expects the number of CNG-powered vehicles to rise to 100,000 by year-end. It will address safety issues by tightening monitoring standards at all stations nationwide, said PTT senior executive vice-president Chitrapongse Kwangsukstith. All motorists whose vehicles were properly modified for using the natural gas would receive PTT cards. The conversion for the truck involved in the incident was was not certified.