The five naval personnel who were killed on Friday night on board warship INS Jalashwa, died due to inadvertently inhaling hydrogen sulphide gas, leaking from one of the compartments of the vessel.
The personnel comprised a repair party, which was working on one of the shafts when the leak took place, a naval spokesman said on Saturday.
The naval personnel were carrying out maintenance work and died by inadvertently inhaling the leaking gas and not due to any fire or any other cause, he said.
Five naval personnel were killed and three injured critically during the naval exercise in the Bay of Bengal.
The deceased sailors have been identified as K V R Krishna Rao, D R Kumar Chaitanya, Ramesh Kumar Nayak, Deepak Shivran, and Narendra Yadav, all members of the repair team.
Among those injured are Lt Cdr Sweth Gupta, Lt Ruchir Prasad and electrician Yatish Pawar.
All the three injured are being airlifted to Port Blair from the ship for further medical treatment.
An Indian Air Force AN-32 transport aircraft has been positioned at Port Blair to bring back the dead bodies to Vishakhapatnam.
The accident took place on board the Indian Navy's latest acquisition INS Jalashwa while the ship was taking part in the naval exercises between Visakhapatanam and Port Blair.