A Russian national was revealed to be the captain of the cargo ship that collided with an American tanker off the coast of England, spilling U.S. military jet fuel into the sea.

Nearly three dozen people were taken to a hospital, Reuters reported, and one remained hospitalized Monday afternoon.

The police in Britain detained the ship’s captain on suspicion of gross negligence after it crashed into an oil tanker that was being operated by the U.S. Navy.