Four employees were today admitted to Jawaharlal Nehru Hospital and Research Centre after they complained of suffocation, Inspector General of Police Pradeep Gupta said.
They were not working in the same section where the mishap occurred yesterday, he told PTI, adding that exact cause of their sickness was not known yet.
Meanwhile, the authorities said that number of casualties in yesterday's mishap was unlikely to go up, with all those affected now out of danger.
"A magisterial inquiry headed by the Durg Additional District Magistrate has been ordered," Durg Collector R Sangeetha said today.
The leakage of carbon monoxide at the plant last evening affected 36 people. Five of them, including two Deputy General Managers, died during the treatment, while the body of Vikas Verma, a contract worker, was found after de-watering the pump house where the mishap occurred, the Collector said.
Prime Minister Narendra Modi called up Chhattisgarh Chief Minister Raman Singh today to inquire about the situation. Modi expressed condolences for the families of the deceased and issued instructions for proper treatment and assistance to be given to those who have taken ill.
Steel Authority of India Limited Chairman C S Verma, who visited the plant this morning, said a high-level inquiry will be conducted and all assistance would be extended to those affected by the leak.
"Of those who were brought to the hospital (yesterday), 21 have been released after first aid and necessary treatment. Nine persons are still admitted in the hospital for observation and medical treatment. Condition of these nine persons is stable and they are out of danger," SAIL said in a statement. Those who lost their lives in yesterday's mishap were identified as Deputy General Managers B K Singh (56) and N K Kataria (56), master technician A Samuel (48), senior operator Yarad Ram Sahu (53), assistant fire station officer Ramesh Kumar Sharma (58) and contract labourer Vikas Verma.
Meanwhile, members of employee unions staged a protest in front of plant's gate today, blaming the management for the mishap.
Governor Shekhar Dutt visited the hospital where the injured have been admitted.
Production at the plant was partially affected due to the mishap and maintenance work was on, a senior plant official told PTI.