Many people were left injured or unwell after the accident. Photo taken from BBC
At least six people are now known to have died from a poisonous gas leak that followed an explosion on Thursday at one of India's largest steel plants, factory officials said.
Noxious gas escaped from a blast furnace while a nearby water pipeline was being repaired at the government-run plant in Chhattisgarh state.
Workers say deaths could have been avoided had there been safety measures in place. The plant has not responded.
About 30 were left hurt or unwell.
Some workers held a protest at the plant on Thursday evening and again on Friday morning, BBC Hindi's Alok Putul reports from the state capital, Raipur.
The main water pump suddenly ruptured on Thursday night, resulting in a loss of pressure in the pipes supplying water to the blast furnace, the company said in a statement.
As the workers were fixing the rupture, gas from the furnace entered the damaged pipes and leaked, it added.
The plant, which is India's first and main producer of steel rails, employs tens of thousands of people.