Houthi rebels are blocking UN access to an unmaintained oil tanker described as a "floating bomb" off of Yemen’s Red Sea coast, which officials say is an environmental catastrophe waiting to happen. The chief of the Iran-backed Houthi rebels is demanding a share of revenue from the sale of about one million barrels of oil aboard the <em>FSO Safer.</em> The UN warned almost a month ago that the ship was at risk of exploding, possibly causing a disastrous oilspill in one of the world’s busiest shipping lanes. It is a dangerous bargaining chip worth tens of millions of dollars. The <em>Safer, </em>once Yemen's main oil export facility, is a floating storage and offloading vessel moored about 50 kilometres north-west of Yemen's port city of Hodeidah, the entry point for most of the war-racked country's humanitarian aid and imports. The <em>Safer</em> has had no maintenance since it fell under Houthi control in 2015, allowing explosive gases to build up in its storage tanks. Experts and Yemeni ministers have been warning for more than a year that the vessel needs urgent maintenance, with <a href="https://www.atlanticcouncil.org/blogs/energysource/why-the-massive-floating-bomb-in-the-red-sea-needs-urgent-attention">a report by the US think tank the Atlantic Council</a> calling it a floating bomb. A rupture could unleash a catastrophe four times larger than the 1989 Exxon Valdez oilspill that poured 260,000 barrels of crude into Prince William Sound Alaska. "Without maintenance, we fear that it will rupture or even explode, unleashing an environmental disaster," the UN's humanitarian chief <a href="https://reliefweb.int/report/yemen/under-secretary-general-humanitarian-affairs-and-emergency-relief-coordinator-mark-17">Mark Lowcock told the Security Council on April 15</a>. Mr Lowcock said that Houthi approval to carry out an assessment of the vessel have been pending since last September. In 1988, Yemen’s national Safer Exploration and Production Operations Company (Sepoc) moored a former Japanese oil tanker 9km off the coast at Ras Isa, a Red Sea port, linking it by pipeline to the Marib oil field in central Yemen. Described by the company that installed it as the largest FSO system in the world, the Safer has a capacity of three million barrels of oil and until 2015 served as Yemen’s main export route for light crude. The ageing vessel is susceptible to corrosion and needs about $10 million (Dh3.6m) in annual maintenance. Inert gas must be regularly injected into the storage tanks to prevent the accumulation of explosive gases. Without fuel to run its generators, this has not happened in years. A stray spark, collision or sabotage attack could cause the vessel to explode. In March last year, Yemeni Foreign Minister Abdulmalik Al Mekhlafi wrote to UN Secretary General Antonio Guterres, warning that the<em> Safer</em> was in a "bad and deteriorating situation" that threatened an "imminent environmental and humanitarian catastrophe". On April 29, Col Turki Al Malki, spokesman for the Arab Coalition against the Houthis, warned that the <em>Safer</em> posed a serious risk of oilspill to the Red Sea. The Houthis agree the vessel poses a threat but they have asked the UN to arrange the sale of oil so they can use the revenues to pay for fuel imports and public salaries. The head of the Houthis' Supreme Revolutionary Committee, Mohammed Al Houthi, warned on Twitter on April 22 of the risk to the environment and marine transport posed by the <em>Safer.</em> On April 30, he wrote: "We call on the UN and the Security Council to put in place a mechanism to sell Yemeni crude oil, including the oil in the <em>Safer.</em>" But a Yemeni oil expert told <em>The National</em> that the condition of the vessel meant it was now unlikely that it could safely offload the oil from where it is moored. "The solution is to tow the <em>Safer</em> to Bahrain" where the vessel can be safely repaired, Yemeni economist Abdulwahed Al Obaly said. Both Houthi and government areas of Yemen are suffering from a lack of fuel and cash, with <a href="https://www.thenational.ae/world/mena/famine-on-the-rise-in-the-middle-east-and-north-africa-1.859239">24.1 million Yemenis in need of aid and 13 million on the brink of famine</a>. The fuel aboard could be worth $80m at current prices. "Fuel shortages in Yemen continue to add to the appalling humanitarian cost of the conflict," said Doug Weir, a director at the Conflict and Environment Observatory, which wrote a <a href="https://ceobs.org/is-an-ageing-oil-tanker-threatening-an-environmental-disaster-off-the-coast-of-yemen/">report into the environmental risks of the <em>Safer</em></a>. "However, the use of the <em>FSO Safer</em> as a bargaining chip carries with it a serious risk of miscalculation. “All of the indications suggest that it poses a grave and imminent threat to the marine environment, and it is critical for parties to the conflict to reach agreement on an independent UN-led assessment as a first step in mitigating the risks that it poses. The UN contracted a company to carry out an initial technical assessment of the vessel last August, but this work is yet to be done. The UN did not respond to repeated requests for comment. But the company contracted to carry out the assessment, Asia Offshore Solutions, said it hoped to begin work shortly. "We've been waiting for the Hodeidah area to be safe enough for our people to go in," Petter Nilsen, the company's managing director, told <em>The National</em>. The delays preventing the UN from accessing the ship also threaten to undermine the Hodeidah agreement, reached in Stockholm in December between the Yemeni government and the Houthis. The two agreed to “a strengthened UN presence in the city of Hodeidah and Ports of Hodeidah, Salif and Ras Issa” and “committed to facilitate and support the work of the UN”. The oil aboard belongs to Yemen’s Ministry of Oil. Even after an assessment is carried out, all parties would need to agree to a salvage operation. “There’s legal, technical, and business obstacles,” Mr Al Obaly said. “They all need to agree on managing the insurance, what to do with the vessel and the oil, and they need to pay the company that would carry it out.” But a spill would cause untold environmental damage and the need for a clean-up that could cost $1 billion. “We must empty the vessel as soon as possible," Mr Al Obaly said. "It could explode any time just because of the weather and the circumstances. “It would be a marine catastrophe. The crude would reach the other coast of [Eritrea]. We’ve seen many cases like this, We don’t need to do the same in the Red Sea.”