Gas leak, accumulated biogas possible causes behind Gulistan blast: DMP
Death toll reaches 21, three arrested
Downplaying the chances of any sabotage, the Dhaka Metropolitan Police has identified the accumulation of biogas in septic tanks or a leak from an abandoned but not fully-closed Titas Gas line as two possible reasons for the explosion in Gulistan on Tuesday.
At least 21 people were killed and more than 100 injured in the explosion and subsequent collapse of the five-storey Queen Sanitary Market, once known as Queen Cafe, on North South Road in the Siddik Bazar area.
"The building had CCTV cameras and round-the-clock surveillance, so sabotage was out of the question," said DMP Additional Commissioner Harun-or-Rashid at a press conference at the DMP media centre in the capital on Thursday afternoon.
However, the explosion-hit building owners had violated the building codes, putting people at risk, the official said.
Police have arrested three people including the owners of the building. The arrestees are building owners Wahidur Rahman, Matiur Rahman and businessman Motaleb Mintu.
They were shown arrested in an unnatural death case filed by the police on Wednesday over the explosion incident.
On Thursday, the third day of the blast, the Fire Service and Civil Defence recovered another charred body from the ruins of the collapsed building, taking the death toll to 21.
Assistant Director of the Fire Service Akhtaruzzaman on Thursday told The Business Standard (TBS) "According to the description given by the family members, the recovered body is of one Mehedi Hasan Swapan. However, the body was badly burned and the identity cannot be ascertained."
When asked about the current condition of the blast site, Mehedi Hasan said, "There are four-five feet of debris in the basement. However, no more bodies are trapped under the ruins according to the information we have."
In the press briefing, DMP Additional Commissioner Harun-or-Rashid, who is also the chief of the Detective Branch (DB), said the DB police traced the history of the building and gave their observations on the matter following the initial investigation.
He said that the explosion originated on the first floor of the building where a restaurant named "Queen Cafe" resided once and its kitchen resided in the building's basement.
The plan was for building a 10-storey unit. By 1992, the basement and the first floor were built. The remaining floors were completed in 2004, Harun said.
Once the spaces on the basement and the first floor were leased, large gas lines were fed into the basement for the kitchen.
The DMP also made a number of observations regarding the cause of the blast. Some of the observations are listed below:
The basement of the building was supposed to have car parking, but there was once a kitchen there. Currently, a commercial establishment called "Bangladesh Sanitary" sells sanitary goods in an underground space of about 1800 square feet, which is completely surrounded by glass. The sanitary shop is cooled by two big air conditioners. There is also a big water tank there. The owners of the building are not sure where the sewage septic tank is located in the seven-storey building. It is believed that the septic tanks of these two buildings are located in the two-and-a-half/three feet alley to the north of the building.
Car parking in the basement would have air ventilation. Had that been in place, there would have been no accumulation of gas and the explosion would not have happened.
The kitchen in the basement was once supplied with gas from a large commercial line. Although the line was closed, the domestic lines for the other buildings were operational. As a result, the Titas gas may leak through the line in the basement. An explosion can occur through a spark near the accumulated gas.
According to the building owners, there is a narrow lane between the main damaged building and the Brac Bank building on its northern side. The septic tanks, outer portion of the AC etc are located in this lane. The blast completely damaged the side walls on this lane. Biogas explosions can cause this.
The building had many large ACs. If the ACs were not serviced from time to time or were faulty, those could also lead to explosions like the one that happened at the UAE visa centre in Gulshan around three years ago.
The DMP official further said a number of government agencies are investigating the incident and the actual cause of the explosion would be known soon.
Rajuk yet to find building documents
Meanwhile, Rajdhani Unnayan Kartipakkha (Rajuk) has yet not been able to locate the file containing documents and permits for the Gulistan building.
Rajuk was also unable to confirm whether the building was legitimately constructed in accordance with the national building code.
"The building was old and so was its file, the hardcopy of which has been stored manually [only files that were approved by Rajuk after May 2019 are digitised]. On top of that, yesterday was a holiday. That's why it is taking time to locate the file," said Tonmoy Das, a member (development and admin) of Rajuk.
Tonmoy also informed reporters that the Rajuk is identifying risky buildings under the Urban Resilience Programme. So far, 232 risky buildings have been identified in the capital. Rajuk recommended the city corporations for taking action against those buildings.