President Donald Trump has confirmed he’s pushing for a ban on US diesel exports, a move the oil industry has been fretting about for weeks. If such curbs came into effect, the ramifications for global and US fuel markets would be enormous. America is the world’s biggest exporter of middle distillates, including diesel and jet fuel.

In the past year, the three biggest buyers of American supplies were Mexico, Chile and Brazil, Kpler data show. But an export ban would also be felt in Europe, where the US is the single largest supplier. A ban would starve the world of vital fuel at a time when it’s most needed.

There’s no certainty it would solve domestic problems either. With America holding on to its fuel, storage would fill up along the Gulf Coast. Refineries would scale back production, affecting other fuels and spurring higher prices. Central banks are already watching fuel costs as they grapple to tame inflation.

“Restricting exports is not a solution to high prices,” says the American Petroleum Institute. “Removing US diesel from the market could instead result in reduced refinery runs, global economic damage and even higher US prices.”