A tanker carrying jet fuel for the US military was hit by a container ship off northeast England on Monday, with the collision igniting a blaze on both vessels, causing multiple explosions and forcing both crews to abandon ship.

The tanker, which can carry tens of thousands of tons of jet fuel, was at anchor when the smaller container ship struck it, rupturing its cargo tank and releasing fuel into the sea, its operator said. Its owner Stena Bulk gave the same details.

Two maritime security sources said there was no indication of any malicious activity or other actors involved in the incident.

Local officials said 32 casualties had been met by ambulances but by mid-afternoon only one remained in hospital.

But there was still a risk of environmental damage, experts said.

The tanker, the Stena Immaculate, operated by US logistics group Crowley, was carrying Jet-A1 fuel when it was struck by the Portuguese-flagged cargo ship Solong while anchored near Hull, Crowley wrote on X.

The tanker is part of a US government programme designed to supply the armed forces with fuel when required. A US military spokesperson told Reuters on Monday it had been on a short-term charter to the US Navy's Military Sealift Command.

The Solong is carrying 15 containers of sodium cyanide, a toxic chemical used mainly in gold mining, and an unknown quantity of alcohol, according to a casualty report from maritime data provider Lloyd’s List Intelligence.

Emergency teams sent a helicopter, fixed-wing aircraft, lifeboats and nearby vessels with firefighting capability to the incident on Monday morning.

"A fire occurred as a result of the allision and fuel was reported released," Crowley said. An allision is a collision where one vessel is stationary.

Crowley said there had been multiple explosions on board.

Environmental Risk

Martin Slater, director of operations at Yorkshire Wildlife Trust, said East Yorkshire’s coast was home to protected and significant colonies of seabirds including puffins and gannets, with many offshore on the sea ahead of the nesting season.

A Greenpeace spokesperson said any impact would depend on factors including the amount and type of oil carried by the tanker, the fuel carried by both ships, and how much of that, if any, had entered the water, plus the weather conditions.

One insurance specialist said the pollution risk was lower than if the tanker had been carrying crude oil.

"A lot depends really on cargo carried, how many tanks were breached and how bad the fire is," the insurance source said.

Mark Sephton, professor of Organic Geochemistry at Imperial College London, added that the relatively small hydrocarbons of jet fuel could be degraded by bacteria more quickly than larger molecules.

"The fact that we are moving into warmer temperatures will also speed up biodegradation rates," he said.

The incident occurred in a busy waterway, with traffic running from the ports along Britain's northeast coast to the Netherlands and Germany, shipping industry sources said.

Maritime analytics website MarineTraffic said the 183-metre (600 ft)-long Stena Immaculate was anchored off Immingham, northeast England, when it was struck by the 140-metre (460 ft)-long Solong, which was en route to Rotterdam.

Ship insurer Skuld of Norway would only confirm that the Solong was covered with it for protection & indemnity (P&I), a segment of insurance that covers environmental damage and crew injuries or fatalities.

Solong's manager, Hamburg-based Ernst Russ, did not immediately respond to a request for comment. Stena Immaculate's P&I insurer, which was listed as Steamship, did not immediately respond to a request for comment.