The barge at the Thoothukudi port in which three workers died of suspected asphyxiation inside one of its ballast tanks on Wednesday had a crack, and the workers were trying to pump out the water so that the crack could be repaired, shipping officials investigating the accident say.

The crack was in the forward of the vessel (front). The workers on the tug that tows the barge had rigged up a diesel-driven pump, opened the manhole door of the ballast tank, and were pumping out the water into the sea. Officials also suspect the integrity of the tanks since the ballast tank at the back of the barge, called aft, was also filled with water, likely coming from the forward ballast tank that had the crack.

In merchant vessels as well as barges, entry into such tanks is typically prohibited unless an Enclosed Space Entry permit is issued by a responsible person of the vessel after ensuring that the tank is well ventilated and levels of oxygen and other gases are found normal. The plan in the Thoothukudi barge was that after the tank was emptied, the crack would be repaired.

Investigators say it appears that the workers found that the forward tank was not emptying and the stagnant water could have led to oxygen depletion and possibly even toxic gases inside the tank. The workers may have gone inside the tank to check on the situation, they say.