At least four workers died on Wednesday and a few others fell ill after inhaling a toxic gas leaked from a unit at Rourkela Steel Plant (RSP) of the state-run SAIL in Odisha, official sources said.
The mishap took place at the Coal Chemical Department of the RSP in the morning, when a total of 10 workers were on duty.
The four were contractual workers engaged by a private company, they said.
"According to a preliminary report, the four workers died due to emission of carbon monoxide gas from the unit," the officials said.
They were admitted to the ICU of the Ispat General Hospital (IGH) where they died and a few others are being treated in the RSP dispensary.
The RSP authorities have ordered a high-level probe into the mishap, they said.