A Japanese chemical tanker sank after colliding with a container ship today, prompting fears of a leak.
Coastguard officials said the 411-tonne Eiwa Maru, carrying 500 tonnes of the thinner xylene, hit the 52,103-tonne Panamanian-registered Ever Rewardat around 7 p.m. last night about 20 miles off the Izu peninsula, 100 miles west of Tokyo.
There were no indications of a major leak after the tanker sank around seven hours after the collision.
A spokesman for the Yokohama disaster prevention centre said that while xylene can be toxic in high concentrations, it is not water-soluble and any that leaked out would float to the surface.
"There it will evaporate, taking from minutes - if there is a strong wind - up to five hours to completely disappear," he added. "So the chance of damage, even to marine life, is likely to be minimal."
The Eiwa Maru'screw of four escaped on a life raft and were picked up by a nearby ship, an official at the Shimoda coastguard station on Izu said. They went to hospital with minor injuries.
Weather conditions were fine and visibility good at the time of the accident, the official said, but he declined to speculate on the cause pending an investigation.
Xylene, used as thinner and to make plastic resins, evaporates rapidly from soil and surface water and sunlight breaks it into less toxic substances.