A port official said he was told the North Sea collision produced "a massive fireball" and the cargo ship's owner said one crew member was missing.

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

British police arrested a man Tuesday on suspicion of manslaughter as they searched for answers about why a cargo ship hit a tanker transporting jet fuel for the U.S. military off eastern England, setting both vessels ablaze.