European airlines may soon be allowed to lean on U.S.-grade fuel to help blunt possible jet fuel shortages tied to the war between the United States-Israel coalition and Iran. The International Air Transport Association has urged broader acceptance of the fuel, while Europe’s aviation safety regulator has issued guidance on how supplies from the U.S. could be brought into the market.

The move matters because the fuel most European airlines currently burn has become far more expensive, with prices up by half since the war began. That surge has increased pressure on carriers that already rely heavily on imports of Jet A-1 from the Gulf region, where supplies have slowed to a trickle since the crisis erupted.

Stuart Fox, in a blog post, said the strain could deepen if the conflict drags on. “European fuel supply could come under pressure if the war in the Middle East continues,” he warned, adding that “it won't be long before we see fuel shortages in some parts of the world.” He also said using Jet A, which is produced at scale outside the Gulf, “could be a practical way to help ease some pressure on existing supply chains.”

The issue turns on two main types of aviation fuel. Jet A-1 is the global standard used in most international aviation operations, including long haul and polar routes, and it has a lower freezing point than Jet A, which is mainly used in North America. Because many U.S. refineries are not set up to produce Jet A-1, shipments from the United States can help, but not fully replace Gulf supply.

On Friday, the European Union said there are no regulatory obstacles preventing European airlines from using either grade, as long as the fuel is handled safely and communicated properly through the supply chain. The European Aviation Safety Agency said a potential introduction of Jet A in Europe “would not generate safety concerns provided that its introduction is properly managed,” but warned that poor handling “could result in an aircraft flying outside of its safe operating limits.” It also said inconsistent availability from airport to airport could raise the risk of mixing up fuel grades and the assumptions tied to them.

The safety agency later issued a bulletin with guidance for fuel suppliers, aircraft operators and airport operators. For now, the question is not whether Europe can legally use U.S.-grade fuel, but whether airlines and airports can move quickly enough to keep planes fueled without creating new operational risks as the war continues to squeeze supply.