Ship-breaking yard tragedy: Experts submit report on deaths of 10 workers
A preliminary investigation has identified dissolved hydrogen sulfide gas in water inside a ship’s tank as the suspected cause of the accident that killed 10 workers at a shipbreaking yard in Chattogram’s Sitakunda.
A team of experts submitted the preliminary report to the Ministry of Industries last Wednesday after inspecting the accident site. However, the investigation is still ongoing.
Md Easir Arafat Khan, a professor of chemical engineering at Bangladesh University of Engineering and Technology (BUET) and head of the expert team, confirmed the development.
The accident occurred on 14 August at Ferdous Steel Ship Recycling Industries in Sitakunda while workers were dismantling the old LNG carrier MT Rashi.
“Our preliminary investigation found the presence of hydrogen sulfide at the site. The gas is no longer present in the air,” Professor Yasir said.
“Our preliminary hypothesis is that hydrogen sulfide was released while the water from the tank was being pumped out, and the accident occurred due to coming into contact with that gas," he said.
Professor Easir stated that the ship has four tanks. Work on one of these tanks had already been completed. The accident occurred while work was underway on the third tank.
According to him, de-ballasting or pumping out ballast water was taking place in that tank at the time. It is during the removal of this water that the dissolved hydrogen sulfide may have been released in the form of gas, at which point the workers came into contact with the gas.
Gas no longer in the air, samples in the laboratory
The expert team visited the site and examined the conditions of the air and water inside the tank. Professor Easir Arafat Khan stated that hydrogen sulfide is currently not being detected in the air at the accident site.
However, samples have been collected to further confirm the presence of the gas in a dissolved state within the water. He said, "We have given the samples for detailed analysis. Once the test results are available, we will be able to be more certain about the condition of hydrogen sulfide in the water and how it was formed or accumulated."
Earlier, immediately following the accident, tests by the Department of Explosives had detected hydrogen sulfide at the scene. Within a few hours of the accident, the Department of Explosives went to the site and conducted tests.
SM Sakhawat Hossain, Assistant Director at the Department of Explosives (Chattogram Office) told Prothom Alo that presence of hydrogen sulfide was detected by their instruments in the section of the ship where the workers were affected.
At that time, the concentration of the gas in the air was 10.8 ppm, meaning there were 10.8 parts of hydrogen sulfide per million parts of air.
According to Sakhawat Hossain, that level was recorded in tests conducted several hours after the accident; these tests did not reveal the concentration of the gas at the precise moment the workers were affected.
Several crucial questions still lie before the expert team. How hydrogen sulfide was formed or accumulated in the tank water, what its concentration in the water was, how much gas was released during the water removal, and to what level the workers were exposed. Answers to these will have to await the detailed test results.
The sources of gas inside the ship's tanks and surrounding enclosed areas have been investigated. Now, the expert team's preliminary investigation has also brought forward information regarding dissolved hydrogen sulfide in the tank water. However, the density of the gas at the time of the accident remains unconfirmed.
Professor Easir Arafat Khan stated that it would not be proper to reach a final decision on the matter before the full investigation is concluded.
Carbon monoxide not found
The expert team is also examining whether any other toxic gas was present at the accident site. Professor Md. Easir Arafat Khan said that in such incidents, both hydrogen sulfide and carbon monoxide can be lethal.
However, carbon monoxide was not found in their tests. He further stated, "We did not find carbon monoxide. We found hydrogen sulfide, specifically in connection with the water inside the tank."
Several crucial questions still lie before the expert team. How hydrogen sulfide was formed or accumulated in the tank water, what its concentration in the water was, how much gas was released during the water removal, and to what level the workers were exposed. Answers to these will have to await the detailed test results.
Three investigation committees are working on this incident. Among them, an 11-member committee from the Ministry of Industries has also visited the site in person to collect information and has even entered inside the ship.
Ministry of Industries Secretary Abdun Naser Khan told Prothom Alo that the 11-member investigation committee is working and will submit its report soon, at which point details will be known.
Initially, nine people died in the Ferdous Steel accident. With one more injured person passing away while undergoing treatment, the death toll has risen to ten. Following the accident, the Bangladesh Ship Recycling Board suspended all operations of the institution.