China is preparing to send underwater robots to investigate the hull of a sunken Iranian tanker that has created oil slicks covering 100 sq km of ocean, marking one of the worst shipping disasters in recent years.
The underwater operation, which will also involve surface vessels and divers, could attempt to plug holes in the hull that are leaking oil, according to the Shanghai Maritime Search and Rescue Centre.
The effort to explore the wreck comes as authorities race to limit environmental damage from the spill.
On January 6 the Sanchi, a 274-metre long oil tanker, was transporting 1m barrels of highly volatile condensate crude from Iran to South Korea when it collided with a cargo ship 160 nautical miles off the coast of China. The collision caused a massive fire in which the 32 crew members apparently perished.
The bodies of three crew have been recovered. Mahmoud Rastad, chief of Iran’s maritime agency, said that there was “no hope” of finding survivors among the 29 still missing.
By Thursday strong winds had pushed the oil, which had formed four massive slicks, away from the Chinese coast and into Japan’s exclusive economic zone. The largest of the four slicks covered 48 sq km, the State Oceanic Administration said.
The SOA said it had collected water samples from 19 spill sites, and determined that water from five sites contained petroleum substances at levels exceeding acceptable standards.
Paul Johnston, from Greenpeace International’s Science Unit in the University of Exeter, said the main priority was no longer salvage and recovery but an assessment of the environmental impact of the spill.
Given that the fuel tanks in vessels such as the Sanchi are located close to the engine room, he said, it was likely that they had remained intact since the initial collision. “In this scenario, it is possible that we will see chronic low-volume leakage over a period of time at the seabed. The impact would remain relatively local,” said Mr Johnston.
Wang Haiyang, an expert on marine ecology, also drew attention to the fuel oil. He said heavy diesel oil in the Sanchi’s fuel tank had apparently leaked. “Diesel continues to burn and is easily dissolved in seawater. This can have some impact on the ecological environment and will last two to three months,” he said.
Additional reporting by Sherry Fei Ju