Eight workers, including three officers, were hospitalised following a gas leak in one of the blast furnaces of the Rourkela Steel Plant on Sunday.
The condition of four of them was critical, sources in the plant said. They were admitted into the ICU of the Ispat General Hospital in Rourkela.
The others were released after first-aid.
Three contractor labourers and two workers were among the eight persons affected by the gas leak, which started at around 6.30 am.