LETTER | I read with relief when Transport Minister Anthony Loke announced that the cabinet has decided for Petronas to gradually end its retail of natural gas supply in Malaysia, with a complete phase-out effective July 1, 2025.

Hence motor vehicles powered by natural gas for vehicles (NGV) will no longer be permitted for registration or licensing for use on Malaysian roads starting from July 1, 2025,

Natural gas is a fossil fuel containing primarily 95 percent methane. Under ambient conditions, methane is a non-liquefiable gas. Hence when filled into cylinders, the gas pressure in the cylinder is close to 3,000 pounds per square inch (psi), which is extremely high pressure compared to normal industrial oxygen gas cylinders with 2,500 psi.

Most cylinders in natural gas vehicles are fibre-wrapped aluminium cylinders designed for filling with natural gases. They do not have a fixed lifespan.

Industrial gas cylinders undergo hydrostatic tests every five years. In the test, the cylinders are inspected for internal and external damages.

When the inspections are within acceptable limits, the cylinder would be hydrostatically tested to one and a half times the filling pressure.

When the cylinder passes the test, it will return to service for another five years. Some cylinders in gas manufacturing sites are many decades old. 

I do not think owners of NGV realise they have to carry out hydrostatic tests of their cylinders regularly.

As the cylinder is on the road all the time, subjected to constant vibrations and movements, the owner needs to check the system regularly for possible gas leaks.

Seriously, the industrial gas industry does not recommend transporting cylinders in an automobile such as in NGV.

Gas cylinders are safely transported in open vehicles such as a lorry. When there is a gas leak, the gas is safely dispersed into the open.

In an automobile, the leaked gas is trapped within the automobile. In the case of methane, the gas has no odour and unnoticed leaks could result in a build-up of an explosive atmosphere.

In addition, natural gas cylinders in NGV are often strapped at the boot or behind the backseat of the vehicle. In an accident, where the NGV-powered vehicle is hit from the back, the cylinder could take the brunt of the impact. The integrity of the cylinder could be compromised, resulting in rupture and explosion. 

The hazardous aspect of a NGV is real and stopping its use is an extremely good decision. Kudos to Petronas for dismantling their natural gas refilling station effective July 1, 2025, to stop the use of natural gas for NGVs.

The views expressed here are those of the author/contributor and do not necessarily represent the views of Malaysiakini.