UN-led efforts to prevent a catastrophic oil spill in the Red Sea took a major step forward on Thursday with the announcement of a deal to purchase a vessel that will remove more than a million barrels of oil from a decaying supertanker that has threatened the region for years.

The FSO Safer has been moored off the west coast of Yemen for over three decades but has not been properly maintained since war erupted across the country in 2015 between Government forces, backed by a Saudi-led coalition, and Houthi rebels.

The decrepit ship has been described as a “time bomb” because it could leak, break apart or explode, unleashing ecological and humanitarian devastation, with far-reaching impacts.

The UN Development Programme (UNDP) is implementing the high-risk project to resolve the threat, as part of a $144 million UN-coordinated operation for the FSO Safer.

UNDP has signed an agreement with international shipping company Euronav to secure a replacement vessel to remove the oil onboard the tanker.

“The purchase of this suitable vessel by UNDP marks the beginning of the operational phase of the UN-coordinated plan to safely remove the oil from the Safer and avoid the risk of an environmental and humanitarian disaster on a massive scale. We must accept that this is a very challenging and complex operation,” said agency chief Achim Steiner.