The United Nations has purchased a ship to remove oil from a tanker on the coast of Yemen, officials said Thursday.

The UN Development Program (UNDP) said it signed a contract to buy a crude carrier from tanker firm Euronav.

What do we know about the tanker?

The FSO Safer tanker has been moored off the coast of Yemen for years, threatening an ecological catastrophe if the dilapidated vessel deteriorates sufficiently to cause an oil spill.

The Safer contains 1.1 million barrels of oil, which is four times as much as what was spilled in the 1989 Exxon Valdez disaster, according to the UN. The Exxon Valdez had a similar payload on board, roughly a quarter of which actually spilled.

An oil spill could clog the Bab al-Mandab strait that stretches between the Arabian Peninsula and the Horn of Africa, blocking shipments headed towards the Suez Canal.

The ship, which is 47 years old, has not been serviced since the start of Yemen's civil war in 2015. The UN has warned that the tanker's structural integrity has deteriorated and it is at risk of exploding.

It was abandoned at the port of Hodeida, which is held by Houthi rebels. The port is a critical gateway for shipments into Yemen, which heavily relies on foreign aid.

What did the UN say about the purchase?

UNDP chief Achim Steiner called the deal a "major breakthrough."

Steiner said that the effort would "avoid the risk of an environmental and humanitarian disaster on a massivle scale."

He added that if all goes "according to plan," the operation would start in early May, following routine maintenance of the ship carried out in China.

The UN had been searching for a solution for years and had appealed for a ship donation or lease, ultimately deciding to purchase the ship. "We had no choice, frankly, but to buy a vessel," UN humanitarian relief coordinator David Gressly said.

The salvage operation is expected to cost $129 million (roughly €120 million). The UN said that $75 million had been received and another $20 million had been pledged.

Steiner warned that the UN could still suspend the operation if it does not secure the remaining funds. "Let me be very clear — this is a risky operation and things could go wrong," Steiner said.

sdi/msh (AFP, Reuters)