A tanker operated by Mitsui O.S.K. Lines Ltd. is believed to have spilled about 4,500 tons of crude oil into the Indian Ocean after colliding with a freighter it was attempting to assist, the company said Tuesday.
The accident may be the largest-ever oil spill involving a Japanese tanker, but it is unlikely to damage coastlines as the spilled crude is light oil and three-fourths of it can be expected to evaporate over the next several days, the Tokyo-based shipper said.
The remaining oil should sink into the seabed within a week, Mitsui O.S.K. said.
The Bright Artemis, a 146,463-ton Singaporean-registered tanker with 23 crew members aboard, said the collision had caused no injuries or damage to the ship's ability to navigate.
The tanker collided with the 10,208-ton Singaporean-registered cargo ship Amar at around 3 p.m. Monday Japan Time when it approached the freighter, which had caught fire, to offer to rescue its crew.
The site of the accident is some 530 km west of Great Nicobar Island, an Indian territory.
The oil spilled from the tanker's two tanks after the collision left a hole measuring about 5 meters by 1 meter on its starboard quarter.
The tanker had taken on 250,000 tons of crude oil in Oman and Saudi Arabia and was heading for the port of Chiba.
The ship's captain is Croatian and most of the crew members are Filipinos, with no Japanese included in the crew.
The weather was fair but the sea was rough at the time of the accident, the company said.