BBC Verify explores how a ship carrying a highly-toxic chemical hit a tanker in the North Sea that was transporting jet fuel for the US military.
The incident occurred before 10:00 GMT, with the Stena Immaculate tanker apparently hit while at anchor by the container Solong, tracking data analysed by BBC Verify suggests.
Thirty-six people have been brought ashore and no-one has needed to go to hospital. But one of the 14 crew members on the Solong cargo ship is missing, the vessel’s owner Ernst Russ has said.
Motion Graphics by Mark Edwards