Of the injured, Moshtaque with 78 percent burn injuries, Asaduzzaman with 75 percent and Tafizul with 68 percent were admitted to Sheikh Hasina National Institute of Burn and Plastic Surgery.
Besides, Faruk, who received five percent injuries, was given first aid and has been kept in observation, said SM Aiyub Hossain, resident surgeon at the institute.
"The throats of three victims were burned and their condition is critical," he said.
Hafizur Rahman, chief executive officer of Security Force Limited, said an explosion occurred near the main gate of the mill where the guards were on-duty.
It is suspected that the explosion occurred due to gas pipeline leakage.