The death toll in the April 14 blast at a power plant run by Vedanta Ltd in Chhattisgarh’s Sakti district has risen to 24, after another injured worker died early Sunday.

Manish Kumar, a native of Sonbhadra in Uttar Pradesh, died during treatment at Raigarh Medical College. Officials said 11 others are still undergoing treatment in hospitals in Raigarh and Raipur. Two of them are in critical condition.

The explosion took place in a steel tube carrying high-pressure steam from the boiler to the turbine at the plant in Singhitarai village. Several workers nearby suffered severe burn injuries. Deaths have been reported over several days.

Four workers died on the spot. Nine others died soon after the incident. Seven injured workers died in hospitals on April 15, one more on April 16 in Raipur, and two more on Saturday.

The victims include seven labourers from West Bengal, five from Chhattisgarh, four each from Jharkhand and Uttar Pradesh, and two each from Bihar and Madhya Pradesh.

Police have registered an FIR under sections related to causing death by negligence and negligent conduct with machinery.

“Eight to ten individuals, including Vedanta Group Chairman Anil Agarwal and plant head Devendra Patel, have been named in the FIR. If more persons are found responsible during the investigation, their names will be added,” Sakti superintendent of police Prafull Thakur had said.

A preliminary technical investigation found that excessive fuel accumulation inside the boiler furnace led to a pressure build-up, which caused the explosion. A report by the Forensic Science Laboratory in Sakti also confirmed this.

Chief minister Vishnu Deo Sai has asked the Bilaspur divisional commissioner to conduct a probe. The district administration has also ordered a magisterial inquiry.

The Opposition Congress has demanded stricter charges of culpable homicide not amounting to murder in the case.