Safer tanker is seen on Monday, June 12, 2023, off the coast of Yemen. Safer has posed an environmental threat since 2015, as it decayed and threatened to spill its contents of 1.14 million barrels into the Red Sea and Indian Ocean. (AP)

A UN-owned ship arrived off war-torn Yemen on Sunday to pump more than a million barrels of oil from the FSO Safer, a Yemeni tanker, to prevent an oil spill.

After years of a Saudi-backed war on Yemen, the Nautica arrived in Yemeni seas at midday and was set to moor alongside the FSO Safer, a rusting supertanker in the Red Sea. The delicate operation to transfer 1.14 million barrels of Marib light crude to the Nautica, which the United Nations has purchased for the purpose, is likely to commence by the end of the week.

Despite thorough safety checks, there is still anxiety about a spill or an explosion. Safer is transporting four times the amount of oil spilled in the 1989 Exxon Valdez catastrophe off the coast of Alaska. “The risk is high.

The risk is very high,” said Mohammed Mudawi, the UN Development Programme (UNDP) project manager for the ship Safer, adding that “But we are hoping with the completion of the project that this will be eliminated.”

Maintenance operations on the Safer were halted in 2015 amid the war on Yemen and obstructions caused by the blockade; the UNDP has warned for years that a catastrophe might "explode at any time."

That said, a significant spill may cause an ecological disaster, damage Yemeni fishing communities, and force the closure of vital ports and desalination plants. According to the UN, the potential spill, which could cost more than $20 billion to clean up, might reach Saudi Arabia, Eritrea, Djibouti, and Somalia.

Operation to empty decaying oil tanker: Yemen

Earlier in May, the United Nations was planning to begin the ''preparatory phase'' during the last week of May to discharge 1.1 million barrels of oil from a decaying ship off the coast of war-torn Yemen to avoid a catastrophic disaster.

UN coordinator for Yemen, David Gressly, told journalists in New York via videoconference that a UN vessel, Ndeavor, docked at the port of Al-Hudaydah on Yemen’s west coast.

Gressly stated that a UN team would inspect the entire vessel and initiate safety steps.

''If all goes according to plan, somewhere late June, early July, we might be able to say that that critical phase of the ship-to-ship transfer could be completed,'' stated Achim Steiner, administrator of the UN Development Programme (UNDP).

The United Nations had launched a fund-raising campaign to finance this operation, anticipating a total cost of $144 million, which in the second phase includes replacing Safer with a safer and more sustainable solution.