Paul Johnston, Head of Greenpeace International’s Science Unit, said:
“This is an evolving situation and accurate information about the amounts of oil spilled already and likely to be spilled in the future is not available. It remains almost impossible to estimate the magnitude of the spill and what the potential environmental impacts might subsequently be.”
“The authorities must ensure there is continued oversight of the spill and that a thorough and systematic surveillance monitoring programme is put in place to assess its ecological significance.”
The Sanchi, which was carrying 111,000 tonnes  of highly-toxic natural gas condensate from Iran, collided with the bulk freighter CF Crystal on 6 January and caught fire, subsequently sinkingin the East China Sea.
 Using the 111,000 tonnes figure revised down from 136,000 tonnes by the Ministry of Transportation
A factsheet on the accident up to 15 January 2018 is here.