The captain of the container ship 'Solong' has been arrested following a catastrophic collision with the oil tanker 'Stena Immaculate' off Britain's Yorkshire coast, as environmental concerns grow over potential oil contamination in the North Sea [1][2].

The German shipping company Ernst Russ confirmed to the BBC that their 59-year-old captain was detained Tuesday evening on suspicion of negligent homicide, as authorities investigate the cause of Monday's collision [1].

British Transport Minister Heidi Alexander announced Wednesday that both vessels are now unlikely to sink, reducing the immediate environmental risk. Plans are underway to tow the 'Solong' away from the coast [1][3].

The incident occurred Monday morning when the Portuguese-flagged 'Solong' struck the anchored US-flagged tanker 'Stena Immaculate', which was carrying 220,000 barrels (35 million liters) of aviation fuel for US military operations [2]. At least one fuel tank was damaged in the collision, causing a significant fire and oil leak [1].

Of the 37 crew members involved, 36 were safely evacuated, with one taken to hospital. One crew member from the 'Solong' remains missing and is presumed dead, according to British Transport Minister Mike Kane [3].

The German Maritime Emergency Command has dispatched the multipurpose vessel 'Mellum' to assist with firefighting efforts and potential oil containment. The ship, carrying specialized equipment and a crew of 20, is expected to arrive at the scene by Tuesday afternoon [1].

Environmental organization Greenpeace has expressed serious concerns about the incident's impact on marine life, particularly noting that the fuel leak occurred near a porpoise resting area [1]. The Hamburg-based shipping company Ernst Russ has denied earlier reports that the 'Solong' was carrying containers of sodium cyanide [2].