CNN cited the Japanese coast guard as saying that the tanker anchored about 5kms off the port of Himeji in western Japan.
Although rescuers recovered seven of eight crew members, the ship’s captain is still missing.
Currently, the coast guard is investigating the cause the explosion on the Shoho Shopping-operated ship.
Agence France-Presse (AFP) quoted Syoho Shipping, the firm which owns the vessel, official Akihiro Komura said that the ship unloaded crude oil at a port in Hyogo prefecture and was virtually empty during the accident.
"I heard that a crew member was using a grinder to remove paint and that seems to have triggered the blast, which we believe could have occurred when the remnants of the oil caught fire," Komura added.
"All the crew members are Japanese nationals. We have confirmed seven out of the eight are alive and one, believed to be the captain, is still missing."
Currently, the coast guard is investigating the cause the explosion on the Shoho Shopping-operated ship.
