Lax monitoring, grave risk | The Daily Star
12:00 AM, June 14, 2016 / LAST MODIFIED: 02:42 AM, June 14, 2016

Use of Counterfeit, Faulty CNG Cylinders

Lax monitoring, grave risk

In March, Abul Quaiyum bought a reconditioned car and was ready to convert the fuel-run vehicle into a CNG-run one from an authorised conversion centre. He knew it would cost him Tk 60,000, but didn't know where best to go. So he asked a mechanic friend for advice.

Authorised centres are expensive, Quaiyum was told, and it doesn't really matter whether he does it from an authorised or unauthorised centre.

So he changed his mind and went to an unauthorised workshop. He saved Tk 20,000 in the process, but following some recent deadly accidents involving gas cylinder explosions, he is now worried about his life. Quaiyum, 40, makes a living out of his rental car and is on the road for about 12 hours a day.

Like him, thousands of car owners have done, and are still doing, the same either to save money or having been misled by mechanics in their neighbourhoods or at unauthorised conversion workshops.

But at a grave risk. In April, two people died and 12 others were injured in separate explosions of gas cylinders in Dhaka and Chittagong. Probe found that the one in the port city happened as a result of using a counterfeit and faulty cylinder. 

“Given the number of roadside CNG conversion shops in different parts of the city and the cheaper rates offered by them, they seem to be an obvious choice,” said Quaiyum.

In recent years, unauthorised conversion centres sprouted like mushrooms in different parts of the city, particularly where the concentration of automobile outlets is high. Most of these workshops are ill- or under-equipped, and are run by mechanics with little or no expertise. They use defective cylinders and other kits, ignoring the risk factors.

In the absence of any designated monitoring authority, they even fit cars with cylinders that are not designed for containing compressed natural gas (CNG).


One little flaw in the cylinder, and the risk can be immense. To be sure, substandard cylinders have many flaws.

Ideally, a CNG cylinder must withstand pressure of around 3,000 pounds per square inch (PSI), which can increase further during refilling. But many of the unauthorised conversion workshops use cheap cylinders designed to contain other gases, such as oxygen. Some of them can withstand pressure between 1,000 and 1,500 PSI. 

This means their chances of explosion are double, said Mohammad Ali Biswas, general manager (CNG) of Rupantarita Prakritik Gas Company Limited (RPGCL), the licencing authority of CNG conversion centres.

Another common feature of CNG cylinders is that they must be seamless; no joint, no welding. But other cylinders, such as those meant for oxygen gas, tend to have a longitudinal seam that is likely to give way under high pressure.       

“An investigation found that one explosion in Dhaka happened because the cylinder was made by welding metal pipes,” Ali said.

Other low-quality equipment and kits used by these unauthorised workshops increase the risk further, said Farhan Noor, general secretary of Bangladesh CNG Filling Station and Conversion Workshop Owners Association, an organisation of owners of authorised filling and conversion centres.

CNG cylinders have a release valve to get rid of excess pressure inside, in case of over refilling. Unskilled mechanics, oblivious to its purpose, often shut the valve off completely raising the risk of explosions.

Md Poltu, who works at Yasin Motors CNG in the city's Dholai Khal, said: “We actually collect the CNG cylinders from old vehicles and sell them.”

Four other cylinder sellers in Dholai Khal and Mirpur said the same.

In almost all the cases of CNG-related explosions, the cylinders were either not meant for CNG or they were modified and welded locally, said Ali.

But why take the risk? First of all, it's cheaper. For conversions, unauthorised centres charge between Tk 40,000 and 45,000 a piece against Tk 65,000 and 75,000 by authorised workshops.

Masud, a car owner and driver by profession, said he installed an oxygen cylinder instead of a CNG one to save money.

Then there is the persuasion by the mechanics who somewhat compels car owners to install substandard cylinders.

The Daily Star correspondents visited about 10 workshops in Mirpur, Dholai Khal and Shajahanpur that install gas cylinders in cars. While most of them sell substandard and used cylinders, all of them sell those without any safety test. One of them was found selling oxygen cylinders instead of CNG cylinders.

One mechanic said, “Customers, looking for a bargain, often ask us to convert the vehicles … most people don't care about the issues [safety]; they just want a better deal.”


The cylinder blast in Savar in April that left two people dead and four others injured could have been avoided had the cylinder gone through the mandatory periodic test.

The cylinder in question had been in use since 2006 without any retest. The container had corroded because of long use and several holes had surfaced on its inside wall, said Monira Yesmine of the Department of Explosives.

“Had the cylinder been tested in due time, its problem would have been detected and the accident avoided,” said Monira, who investigated the accident.

According to the international guidelines and a 2002 government circular, gas cylinders must undergo fitness tests every five years. But cylinders of some 1.5 lakh vehicles in the country have not been tested since their conversion into CNG years ago, officials said.

There are around 3 lakh vehicles -- private cars, buses, trucks, and of course, auto-rickshaws -- that were converted into CNG-run from some 180 authorised conversation centres. There are thousands more that were converted from unauthorised centres.

Some 15 to 20 authorised workshops currently import cylinders, which must undergo check-ups by the RPGCL and the Department of Explosives.

For the five-yearly mandatory retest, there are only 11 authorised centres in the country. Of them, only seven to eight are operational. 

In Bangladesh, the use of CNG as automobile fuel started in the mid-1980s and it became popular after 2001. But fewer people are now converting their vehicles mainly due to the rising gas prices. 


Bangladesh CNG Filling Station and Conversion Workshop Owners Association submitted a proposal to the BRTA on several occasions so that car owners submit their cylinder test and conversion report as a prerequisite for obtaining fitness certificates. But the government body did not pay any heed, said Farhan Noor, general secretary of the Association.

The Association has also been urging the government, particularly the RPGCL, to take action against the unauthorised workshops for long, but in vain.

Contacted, officials of three relevant authorities shifted the blame on each other.

Nurul Islam, director (engineering) of the BRTA, said they issued fitness certificates of vehicles in line with the Motor Vehicle Ordinance 1983 and Motor Vehicle Rule 1984.

"Since CNG-run vehicles were not around when the Ordinance and the Rule were formulated, these have no mention of CNG," he said, adding that, they could not deal with the issues related to CNG. But talks to amend the law are underway, he said.

Nurul said the RPGCL was responsible for matters concerning CNG.

Asked, Mohammad Ali of the RPGCL said they were empowered only to give licences to CNG conversation centres and filling stations and to oversee whether these stations and centres were following the government guidelines.

The RPGCL had nothing to do with unauthorised centres, he added.

The Department of Explosives, which gives licences to the test centres and conducts investigation after any major accidents involving CNG-run vehicles, also shrugged off its responsibility.

Its chief inspector, Shamsul Alam, said the BRTA could play a role in taking action against unauthorised conversion centres.

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