However, they are yet to make contact with anyone from the owners' side. It is impossible to move the cylinders without the cooperation of the owners. As a result, it is hard for the fire fighters to assume whether there are any people under the cylinders or not. It is also impossible to estimate how many workers were inside the factory during the time of the blast as the owners have not contacted them yet. So far they have recovered six bodies and 33 injured persons from the factory.

Earlier, a massive fire broke out after a sudden explosion at the Seema Oxygen Plant in Kadam Rasul area of Chattogram’s Sitakunda upazila on Saturday after. The explosion jolted the entire area within one square kilometre of the factory.

Metal fragments were scattered all around due to the blast. A sheet of iron flew half a kilometre away from the spot of the explosion.

Oxygen is produced at the Seema Oxygen Factory in three shifts. Some workers in the evening shift were refuelling oxygen at the time of the explosion. A total of 150 workers work in the factory in three shifts, 50 in each. Some four to five workers are engaged in refuelling.

The fire service suspects that the explosion occurred at the time of filling the oxygen cylinders. This factory is a sister concern of the Seema Group. The business group also has a rod factory and a shipwreck business.

Earlier, on 4 June last year, some 50 people were killed in an explosion at the BM Depot in Keshabpur of Sitakunda. The Seema Oxygen Plant is nearly one kilometre away from the BM Depot.