The White House has not ruled out foul play as investigators work to uncover what caused a cargo ship to crash into a U.S. oil tanker off the coast of England.

One crew member on the container ship Solong is presumed dead and British police arrested the vessel's captain for manslaughter. The ship smashed into a U.S.-flagged oil tanker, Stena Immaculate, that was transporting jet fuel for the U.S. military.

The accident released jet fuel into the sea, raising environmental concerns as both ships caught fire.

White House on 'foul play'

The management company operating the oil tanker, Crowley, said the ship was carrying 220,000 barrels of jet fuel. It's unclear how much was spilled into the sea, but there are fears of grave damage to wildlife.

"It’s a miracle they didn’t all die. The fog was pretty horrendous," a trawlerman involved in the rescue told The Sun. 

"We were two miles away when the mayday call came in. When we approached it was very scary. We could see the plumes of smoke. There was a really strong smell of fuel burning."

All of the crew members on both ships were rescued except one individual from the Solong, a Portuguese cargo ship with a crew of Filipinos and Russians. A search for the missing sailor was called off and he is presumed dead by British authorities.

The investigation into the disaster is being led by the U.S. and Portugal. At this time, foul play is not being ruled out by the U.S., a senior White House official told gCaptain.

Captain arrested

The Stena is one of ten commercial ships contracted to the U.S. government to carry fuel for the military when needed. The oil tanker was anchored in the North Sea when the Solong suddenly "came out of the blue," an anonymous American crew member on the Stena said.

The oil tanker was preparing for a berth to open up at the Port of Killingholme on the River Humber, a tidal estuary on the eastern coast of England, at the time of the collision.

British police arrested the 59-year-old captain of the Solong, a Russian national who was not named, for gross negligence manslaughter.

"Our thoughts are with the family of the missing crew member, and I have appointed family liaison officers to make contact and provide support to the family," Humberside Police Chief Superintendent Craig Nicholson said.

The German company that owns the cargo ship, Ernst Russ, also expressed sympathy for the family of the missing man.

While the fire on the Stena has died down, the Solong was still burning Wednesday.