Mark Williams, global head of refining, trading and marketing for Royal Dutch Shell, said exporting diesel and other refined products from the United States used to happen fairly irregularly but is now becoming much more common.

"It's growing as a new business," he said, although he cautioned that the United States would probably not become a huge exporter of fuel.

Still, the ability to export oil is good news for Shell and other oil companies like Exxon Mobil, BP and Chevron. They can use their extensive and modern refineries in the United States to make gasoline for the rest of the world.

But it may be bewildering for American drivers, who could experience record high gas prices next year even though U.S. demand could hit the lowest level in a decade, said Tom Kloza, chief oil analyst at the Oil Price Information Service.

"I can understand it, from a truck driver's perspective," said Kloza. "You're paying $4 or $4.50 a gallon to run your rig, yet we're exporting the crap out of this fuel. I'd be outraged too."

Still, he cautioned against restrictions on exports of diesel or gasoline, a move he expects politicians to at least talk about in 2012.

There's nothing forcing oil companies to bring crude to the United States to refine, Kloza said, noting that the refining industry employs thousands of workers.

"If you restrict exports, you'd really be looking for trouble," Kloza said. "You'd just see the refining and the jobs go offshore."