The East Yorkshire coast is home to a wealth of marine life and seabirds – but yesterday’s dramatic collision in the North Sea between an oil tanker and a cargo ship could put that at risk.

The Portuguese-flagged cargo ship, the Solong, was previously thought to have been carrying 15 containers of highly toxic sodium cyanide when it struck the tanker. The US-flagged Stena Immaculate, which was moored 10 miles off the coast, had 220,000 barrels of jet fuel on board, which is now leaking from its ruptured cargo tank into the water. There were widespread fears that a combination of burning jet fuel and toxic chemicals “could cause major environmental damage”, said ITV News.

The company that owns the Solong, Ernst Russ, confirmed this afternoon that its ship was not, as first thought, carrying sodium cyanide at the time of the collision. “There are four empty containers that have previously contained the hazardous chemical, and these containers will continue to be monitored,” a company spokesperson told the press.

That is “good news for wildlife”, said The Times. Sodium cyanide, which is used primarily for metal cleaning and photography, can be “highly toxic”. If it gets wet, it releases a “toxic, flammable hydrogen cyanide gas”, said ITV News.

The leaking jet fuel is “highly volatile”, so “much surface liquid” will evaporate, said Alastair Hay, a professor of environmental toxicology at the University of Leeds. According to the US-based National Oceanic and Atmospheric Administration, “aquatic organisms that come into direct contact” with jet fuel “may be killed” but “small spills in open water” may not actually kill large numbers of fish.

Pollution from the collision, especially if contains toxic chemicals, could have “devastating consequences”, said the New Scientist. Those waters are “home to internationally significant populations of breeding seabirds”, such as puffins and gannets, and on the migration routes for wading birds and waterfowl. Harbour porpoises and grey seals also breed nearby. Chemical pollution can “directly impact” those species, and have “long-lasting effects on the marine food webs that support them”, said Tom Webb, a biosciences lecturer at the University of Sheffield.

Conservation charities are “bracing for what could be nasty”, said Sky News, but the extent of the environmental impact will depend on weather and sea conditions: “wind, waves and currents” all affect how spills spread. It also matters how quickly any spills can be cleaned up. “Usually the slower the response, the worse the impact.” But, with fires still burning, spewing “clouds of filthy black smoke” into the air, authorities have so far been unable to get close enough to assess the damage.

What’s potentially worse is the oil both ships were carrying to power their journeys. That’s a “dirtier, heavier kind of oil”, probably marine gas oil or heavy fuel oil – “horrible stuff”. “Cheap, thick and tar-like, it can smother animals and is extremely difficult to clean up. Let’s hope this isn’t swimming around the North Sea already.”

What next?

The coastguard has started estimating the “likely counter-pollution response”, said Sky News. That might involve “numerous public bodies”, including the Department for Environment, the Environment Agency, and the Maritime and Coastguard Agency.

The Solong has drifted south and could sink within hours, said transport minister Mike Kane. He told MPs that tugboats were in the area to “ensure the Salong remains away from the coast”.

If there is any chemical spill, the clean-up will require careful precautions, said Seyedvahid Vakili, a maritime expert at the University of Southampton. “Given the chemical’s high toxicity, specialised hazardous material teams are needed for clean-up operations,” he told The Telegraph.

In the meantime, the leaking oil and fuel could already be leaving a “toxic legacy” for “ocean wildlife”, said Hugo Tagholm, executive director of sea-protection charity Oceana UK.