Up to 1.1 million barrels of oil could spill into the Red Sea causing a disaster four times worse than the 1989 Exxon Valdez spill, the United Nations Security Council heard on Wednesday.
Time is running out to prevent a dilapidated oil tanker stranded near Yemen from causing a "looming environmental, economic and humanitarian catastrophe," United Nations Environment Programme chief, Inger Andersen, warned.
The Yemeni-government owned tanker, FSO Safer, started taking on water in May. If its oil does spill it could cause irreversible damage to the Red Sea's rich biodiversity, including coral reefs and mangroves.
"Cleaning it up afterwards is not a viable option," said U.S. Amb. Kelly Craft.
The damage would also have severe economic implications for at least 1.6 million Yemeni people, said Mark Lowcock, the U.N. humanitarian affairs chief. "Essentially every fishing community along Yemen’s west coast would see their livelihoods collapse."
Nearly all of those communities at risk already require humanitarian aid because of the years-long war in the Arab world's poorest country, he added.
The conflict, which began in 2014, has seen Iran-aligned Houthi Shiite rebels attempt to topple the internationally-recognized government by taking control of the capital Sanaa. A Saudi-led coalition has been supporting the government in fighting the rebels.
The tanker was built in 1974 and has been regularly inspected by the U.N. But it is moored in territory controlled by the Houthi militia, which has blocked access.
Last week, Secretary of State Mike Pompeo condemned the militia for blocking the U.N. mission.
"The Houthis must grant access before this ticking time bomb explodes," he said during a briefing.
U.N. agencies have been raising the alarm of the risk posed by the tanker for more than a year, Lowcock said Wednesday.
Concerns were heightened in May when a leak sprung in the engine room, creating a risk of explosion. Lowcock said the leak was relatively small and divers were able to patch it up and contain it. However "it is impossible to say how long it might hold," he added.
The U.N. has proposed a plan to repair the damage and enable the oil on board to be salvaged and sold, providing income to local workers, according to the Yemeni government.
Yemen's foreign minister, Mohammed Al-Hadhrami, told the Security Council that the government has accepted the U.N. plan, but said the Houthi militia was not cooperating.
Al-Hadhrami also warned that giving the Houthis access to the government-owned tanker "will not solve the problem, and it will enable them yet again to hijack the issue in the future, when the pressure is lifted."
Lowcock said while the Houthis have rejected the U.N. mission, the Houthi militia last week announced it had changed its position.
However, he cautioned that permissions were promised in August 2019 only to be cancelled by the Houthis the night before deployments.
Reuters contributed to this report