Coast Guard officials in the United Kingdom called off the search for a missing crew member as fires continued to burn aboard two vessels following a collision between a cargo ship and an oil tanker in the North Sea, authorities confirmed on Tuesday.

The crash on Monday morning between the cargo vessel and a tanker carrying jet fuel for the United States military off England's eastern coast ignited both ships, causing multiple explosions and forcing both crews to abandon ship.

The incident sparked a major rescue operation involving lifeboats, Coast Guard aircraft and commercial vessels in the North Sea. Environmental concerns have been raised about the impact on wildlife after it was confirmed that jet fuel had been released into the sea, the BBC reported.

Search ends

The Coast Guard announced that efforts to locate the missing person from the Solong, a Portugal-registered container ship, were terminated after "an extensive search" in the wake of the collision with the anchored Stena Immaculate tanker.

Maritime operator Crowley, the US company that manages the Stena Immaculate, reported that the explosions caused the release of its Jet A-1 fuel cargo.

According to maritime intelligence provider Lloyd's List, the Solong was transporting containers of sodium cyanide, a chemical that produces toxic gas when in contact with water. However, shipping company Ernst Russ, which owns the Solong, confirmed on Tuesday that there was no sodium cyanide on board.

"There are four empty containers that have previously contained the hazardous chemical and these containers will continue to be monitored," Ernst Russ said in a statement.

Martin Slater, director of operations at the Yorkshire Wildlife Trust, told ITV News that jet fuel leaking into the Humber estuary could be "devastating for the wildlife of the estuary", including important fish stocks and tens of thousands of migrating birds.

While initial reports suggested all crew had been safely evacuated, Ernst Russ later revealed that one crew member was unaccounted for.

Coast Guard divisional commander Matthew Atkinson provided the details: "Thirty-six crew members were taken safely to shore, one person was taken to hospital.

"One crew member of the Solong remains unaccounted for. After an extensive search for the missing crew member, sadly they have not been found and the search has ended."

He added that "an assessment of any required counter-pollution response is being carried out by the Maritime and Coastguard Agency".

Ship tracking tool Vesselfinder showed the US-flagged tanker was anchored when the incident occurred. Marine Traffic website data indicated the vessel had departed from a Greek port in the Aegean Sea and was en route to Hull, UK while the Solong was bound for Rotterdam, Netherlands, The Guardian newspaper reported.

The UK's Marine Accident Investigation Branch stated investigators would assess the collision, with officials gathering evidence to determine the next steps.

Agencies contributed to this story.