Six workers died in a carbon monoxide leak at a steel plant of Brazilian firm Gerdau at Tadipatri in Andhra Pradesh's Anantapur district on Thursday evening.
Police said the tragedy struck when tests were being done after maintenance work in the unit. Two workers died on the spot and four others in hospital.
Five others who developed serious health complications were undergoing treatment. A rescue operation was on till reports last came in.
The plant has a capacity to produce 300,000 tons of steel a year. Gerdau is a leading producer of long steel in the American sub-continent. It is one of the largest suppliers of special steel in the world.
In 2007, Gerdau entered into a joint venture with Kalyani Steels Limited to acquire SJK Steel Plant.
The company said in a statement: "Gerdau immediately provided medical assistance and the workers were sent to the local hospital. The company is assisting the family of the victims and is working to determine the cause of the accident."
