Kochi: Five people died and several others were injured in a blast inside the water ballast of the Oil and Natural Gas Corporation (ONGC) tanker ship Sagar Bhushan at the Cochin Shipyard here in Kerala on Tuesday.

The Cochin Shipyard management has announced a probe by an internal committee.

The blast occurred at around 9.45 a.m. Nine workers were engaged in welding inside the water ballast when the blast occurred, killing five of them, while four were injured. Of the four, the condition of one worker is serious with 45 per cent burns and is on ventilator support. The condition of the other three is not that serious, officials said.

The tanker ship has dry-docked at the Cochin Shipyard for a month for repairs and maintenance. All the dead are from Kerala.

About 10 workers who were engaged in works away from the water ballast suffered small injuries when splinters from the blast hit them.

Those working on the tanker during the blast included mostly daily wagers and contract workers since Tuesday is a holiday for regular shipyard workers.

Shipyard CMD Madhu S. Nair told the media about the internal probe committee.

“Since we come under the Factories and Broilers Department, their officials will come, besides those from the Director General of Shipping to find out what happened. We do follow stringent safety practices and even today morning [Tuesday], as per the safety protocols, the amount of gas in the water ballast was checked,” said Nair.

“Since there was a loud noise, there may be a chance that gas got consolidated in the water ballast since welding is done using two different gases. Every aspect will be probed and all expenses on injured workers met by us,” he said.

In a statement, ONGC said “The cause of the incident is being ascertained.”

A ballast tank is a compartment within a ship or other floating structure that holds water to provide stability to the vessel.

Kochi City Police Commissioner M.P. Dinesh told the media: “The dead include some who apparently choked on smoke after the explosion.”

He also said that a probe had been ordered.

A trade union leader present at a private hospital here said nine injured workers were admitted there.