There were three people on board at the time of the incident, and one of them is still missing by Tuesday morning.
The HD06 vessel with 1,000 tons load capacity, registered in the Mekong Delta's Long An Province, was sailing near the Bien Hoa Inland Container Depot in Bien Hoa Town of Dong Nai Province as its engine exploded and started burning at around 6:30 p.m. Monday.
Eyewitnesses said the fire rose tens of meters high and quickly spread to the cabin where the three were staying.
Rescuers rushed to the scene right after they saw the fire, which took them two hours to put off.
They found two crew members suffering critical burns in the cabin and rushed them to hospital but they succumbed to the injuries later.
The oil cargo is left intact. Police are investigating further and continuing searching for the remaining crew member.