The accident occurred in March last year when the ship Solong collided with the Immaculate, which was anchored in the North Sea.
A large aircraft fuel tank ruptured, contributing to extensive fires. In addition, large quantities of plastic pellets were spilled into the sea. Over 16 tons were later cleaned up on beaches in Lincolnshire, UK.
A Filipino crew member from the Solong disappeared during the accident. He has never been found and is presumed dead.
Now a jury has convicted the Russian captain of causing the crew member's death, British media report.
The penalty will be announced at a later date.
The trial was held at the Old Bailey in London.
