Grimsby (United Kingdom) (AFP) - British police on Tuesday arrested on suspicion of manslaughter the captain of a ship that crashed into a tanker in the North Sea, sparking a massive blaze and leaving one crew member missing, presumed dead.

Investigations have already started into what led the cargo ship to strike the tanker carrying jet fuel on Monday, as fears remained of possible harm to the area’s marine and wildlife.

The UK Coastguard, which led the operation, rescued 36 people on Monday, including all of the 23 crew on the US-flagged Stena Immaculate tanker, which had been chartered by the US military.

But a missing member of the Solong cargo vessel crew was “likely deceased”, UK under-secretary for transport Mike Kane told parliament.

Humberside Police in northeast England said they had arrested a 59-year-old man on suspicion of gross negligence manslaughter in connection with the collision.

Ernst Russ, owner of the cargo ship, then issued a statement saying that it “can confirm that the master of the… Solong has been detained by Humberside police in the UK”.

“The master and our entire team are actively assisting with the investigations,” it added.

Kane said the fire on the Stena Immaculate “appears to be extinguished” but this was not immediately confirmed by the Coastguard.

“The Solong is still alight and the fire on board the Stena Immaculate has greatly diminished,” the UK Coastguard said.

The Coastguard was closely monitoring the Solong, which had broken free of the tanker overnight and was limping southwards, accompanied by four tugboats, including one which had a line attached to the stricken vessel.

- No sodium cyanide -

Transport Secretary Heidi Alexander said she met the Maritime and Coastguard Agency’s chief executive Virginia McVea on Tuesday and was “pleased to have been informed that early indications suggest that both vessels are now expected to stay afloat”.

AFP photos taken during a helicopter fly-over showed smoke still pouring from the Solong, while a large hole could be seen in the side of the Stena Immaculate.

The accident occurred at around 09:48 am (0948 GMT) on Monday when the Portuguese-flagged cargo ship ploughed into the tanker, anchored about 13 miles off the northeastern port of Hull.

According to data collected by website VesselFinder, the collision displaced the tanker by “more than 400 metres”.

The Stena Immaculate was on a short-term US military charter with Military Sealift Command, according to a spokesperson for the command, which operates civilian-crewed ships for the US Defense Department.

Crowley, the US-based operator of the Stena Immaculate, said the crash had “ruptured” the tank “containing A1-jet fuel” and triggered a fire, with fuel “reported released”.

The Stena Immaculate was carrying around 220,000 barrels of jet fuel, Crowley confirmed.

In a later statement, the company said it was unclear how much fuel had been released but that an initial review suggested it was “limited” due to evaporation and exposure to fire.

There was “no evidence of foul play”, Kane said in his statement to parliament.

The German owners of the Solong on Tuesday said that the container ship was not carrying sodium cyanide, as had been reported the previous day.

“We are able to confirm that there are no containers on board with sodium cyanide (inside),” Ernst Russ said.

Kane said that “no signs of pollution from vessels is observed at this time”, but that the situation was being monitored.

- Environmental concerns -

Dutch maritime servicing company Boskalis told the Netherlands’ ANP news agency it had been tasked with salvaging the Stena Immaculate and was also measuring the atmosphere around the vessel for potential toxic fumes.

UK Housing Minister Matthew Pennycook said the investigation was being led by US and Portuguese authorities, since the vessels were sailing under their flags.

“We’re obviously very alive to the potential impact on the environment,” he told Times Radio, but added that the Coastguard was well equipped to deal with any oil spills.

Paul Johnston, a senior scientist at the Greenpeace Research Laboratories at Exeter University, said: “We are extremely concerned about the multiple toxic hazards.”

There are several nature reserves along the Humber estuary.

“The good news is it’s not like a crude oil spill,” Ivor Vince, founder of environmental risk advisory group ASK Consultants, told AFP.

“Most of it will evaporate quite quickly and what doesn’t evaporate will be degraded by microorganisms quite quickly,” he said.

Crowley said in its later statement that UK agencies were closely monitoring air quality and possible public health impacts, but “both are currently measuring low or within normal levels”.