A collision between an oil tanker and cargo ship in the North Sea has raised fears of coastal pollution and damage to marine protected areas.
The incident took place off the coast of England on Tuesday, triggering a large explosion and major rescue operation.
It occurred after US-flagged ship Stena Immaculate, which was anchored about 20 kilometres off the north-east Yorkshire coast, was hit by cargo container Solong.
What pollutants were on the ships?
The Stena Immaculate tanker was carrying about 220,000 barrels of kerosene, a petroleum derivative used as jet fuel, when it was hit.
Crowley, the ship's operator, said one of its tanks containing kerosene had been ruptured, and that a leak had been reported.
It's unclear what cargo was being carried by the Solong.
The ship's owner, German company Ernst Russ, on Tuesday, local time, denied reports that sodium cyanide, a chemical compound that produces a highly flammable and toxic gas when in contact with water, was on board.
The Solong was carrying empty containers that had previously contained the "hazardous chemical", it added.
Both ships were also carrying their own fuel, which could be "marine diesel oil" or "heavy fuel oil", according to Nicolas Tamic, deputy director of Cedre, a French centre specialising in accidental water pollution.
Heavy fuel oil is lighter and dissipates more quickly in the environment. Mr Tamic said "the problem will have to be dealt with" if the ships were found to be carrying heavy fuel and not marine diesel oil.
What are the environmental risks?
The area where the collision took place is close to the Southern North Sea and Holderness marine protected areas, whose seabeds are known for their rich fauna and flora.
The coastline around the Humber Estuary is home to many species of birds, particularly waders and other waterfowl.
"Chemical pollution resulting from incidents of this kind can directly impact birds, and it can also have long-lasting effects on the marine food webs that support them," Tom Webb, lecturer in marine ecology at the University of Sheffield, told AFP.
Martin Slater, director of operations at Yorkshire Wildlife Trust, said he was "very concerned" about the threat to birds, particularly colonies of puffins, razorbills, gannets and kittiwakes, which were gathering offshore before nesting season.
"If pollution spillage enters the Humber, this could potentially be devastating for the wildlife of the estuary, including important fish stocks and tens of thousands of overwintering and migrating birds who use the mud flats."
Is there a risk of an oil spill?
According to experts, the risk of an oil spill remains low.
The UK government said on Tuesday there was presently "no sign of pollution" from the two ships.
Kerosene is "not persistent" like crude oil, Ivan Vince, director of the firm ASK Consultants, specialising in environmental risk security, told AFP.
"Most of it will evaporate quite quickly. And what doesn't evaporate will be degraded by microorganisms.
"So we're talking about a week or two, and it should be all gone."
Nancy Kinner, director of the Center for Spills in the Environment at the University of New Hampshire, said that jet fuel's volatility means it "does not tend to make tarballs, evaporates from the surface faster, and tends to dissolve into the water column faster than crude oil".
"The severity of the impacts definitely depend on the amount of fuel that is released upon the surface unburned. The magnitude of the fire suggests that much of the fuel burned in place," she said.
The probability of the toxic hydrocarbons making it to wildlife refuges on the coast depends on the water currents, Ms Kinner added.
"What could be a bigger problem is if the sea birds land, fly close to the surface, or feed on materials they mistake for food on the water that contains the jet fuel slick."
Kerosene does not tend to cause oil spills but it creates "atmospheric pollution when burned", Mr Tamic said.
AFP/ABC
