What could have caused the deadly Siddique Bazar explosion, and how to prevent it in future?

Authorities and experts have multiple theories, but the ongoing investigations have yet to come up with any conclusive reason for the blast that claimed the lives of close to two dozen people so far

It has been three days since the explosion that left 22 people killed, and scores injured at Old Dhaka’s Siddique Bazar, but the investigators have yet to come up with a definitive cause or source of the deadly blast.

Explosives experts confirmed that the evidence collected from the scene does not indicate any act of sabotage.

On Thursday, Home Minister Asaduzzaman Khan Kamal also said the investigators found no traces that could indicate an act of subversion.

He could not confirm the source or cause of the explosion either.

“We are still working on it. But we’re yet to draw a conclusion about what caused the explosion,” he said while speaking to journalists.

Massive explosions and subsequent fires that devastated lives and assets are familiar phenomena in Old Dhaka. In the last 15 years, multiple explosions and fires, notably in Churihatta and Nimtoli, rocked the area, but illegally stored chemicals were somewhat responsible for all those incidents.

The Siddique Bazar explosion and fire had no connection with chemicals.

SO, WHAT COULD HAVE CAUSED IT?

Dr Syeda Sultana Razia, a professor of BUET’s chemical engineering department, said that except for leakage from the underground gas line, she does not see any other reason that could cause such devastation.

“It’s a shopping mall. Households and malls usually do not contain items that could cause a deadly explosion. In my opinion, leakage from the gas lines could cause it,” she said while speaking to bdnews24.com

The four-decade-old building was known as the ‘Queen Sanitary Market’ in the area as it housed multiple shops which sell household bathroom and toilet fittings. Some business enterprises have offices there, and some residential flats are on top floors.

Md Manikuzzaman, assistant director of Fire Service and Civil Defence, has a different theory about the cause- phosgene gas created from the sewage of the sceptic tank of the building.

“If the tanks are not cleaned regularly, this highly flammable gas could be produced from the sewage and cause such a massive explosion if it comes into contact with power or gas lines,” he said.

An engineer with Dhaka WASA who sought anonymity, concurred with the theory.

“If the gas is stuck in an enclosed space, the danger of an explosion increases proportionally,” he said.

Dr Razia, however, dismissed the phosgene gas theory.

“Small volume of methane sips from sewage, which would not cause such a deadly explosion,” she said.

In her argument, she presented the case of the deadly Moghbazar explosion two years ago to support her theory of gas leakage,

“The Moghbazar blast was caused by the gas leaking from the line in an enclosed space. Something similar may have happened in Siddique Bazar as well.”

The senior BUET professor also opined that the lack of space between households and other establishments in Old Dhaka had worsened an already bad situation.

“Houses and establishments in the olden days were spacious, so the chances of leaked gases stored in an enclosed space were slim. These days, households have limited spaces with many enclosed corners, which means gases may get stuck in a specific place if leaked,” she said.

Validating the theory, Dr Razia’s colleague from the civil engineering department, Dr Mehedi Ahmed Ansary, said there must be a flaw in the ventilation system in the building.

“The shockwave was severe. Which means gases were being leaked for a long time due to some flaws in the distribution system,” he said.

The police investigators have multiple theories.

The ground zero of the blast identified by the police inside the building somewhat indicates that it originated from a new glass-made store in the basement of the building.

The basement previously housed the kitchen of a restaurant on the ground floor, and the kitchen had a commercial gas line, according to a police press note.

Records show that the line was later shut down, but investigators posited that gas might have been leaked from the closed line.

Police are also enquiring whether the air-conditioning units active in the building could have caused the blast as such or not.

PREVENTION

Both Dr Razia and Dr Ansary from BUET stressed vigilance and monitoring to prevent such deadly incidents in the future.

“Monitoring and vigilance are the keys to preventing future incidents as such. Authorities need to keep checking the status of gas lines.

There’s no other easy way,” she said.

Dr Razia highlighted the importance of introducing community fire drills, especially in densely populated areas like Old Dhaka.

Dr Ansary emphasised the necessity of strengthening building compliance.

“We witnessed some of the deadliest fire incidents in Bangladesh in Shakharibazar, Churihatta and Nimtoli. These are all repeat incidents. Since monitoring isn’t ideal, nobody cares about compliance.”

“Three crucial elements inside the building- structure, fire prevention and electrical system and gas supply and plumbing- must be recertified regularly. If authorities can impose such strict measures, we may have a chance to avoid such repeat incidents,” he said.