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By Timothy Gardner and Kristen Hays
June 27 (Reuters) - All U.S. crude that is processed by a distillation tower, not only light oil known as condensate, is exempt from the 40-year crude export ban, U.S. government and industry sources said on Friday.
The Department of Commerce determined this week that two companies that produce condensate, a light oil, can export the petroleum if it is processed by a distillation tower.
The sources said any crude that goes through the process can also be exported, potentially widening the amount of petroleum U.S. producers can send to markets abroad.
The Department of Commerce told Irving, Texas-based Pioneer Natural Resources and Houston-based Enterprise Product Partners this week that they can export crude that has been lightly processed after they asked the department for clarification.
Some oil field equipment called stabilizers can be adjusted to qualify as more complicated distillation towers, which could further widen what kind of petroleum can be shipped, said one of the sources.
In a ruling earlier this year, the Department of Commerce told Pioneer and Enterprise that processing their oil through a condensate stabilizer - a much cheaper, easier form of processing that simply separates light petroleum gases from crude oil - would also qualify it for export.
By focusing on how the oil is treated, rather than what it is, the Department of Commerce ruling appears to open an option for companies that produce traditional crude to get around the crude ban by lightly boiling their own oil.
A distillation tower is a type of refining equipment typically used to heat crude oil to the point that it separates into refined fuels like gasoline and naphtha.
The new interpretation of the ruling, which has not been previously reported, will add to the intense speculation over how much of the U.S. shale oil boom might reach overseas markets.
Many things about the regulations remain unclear, however. For instance, it is unclear how the Commerce Department would define a distillation tower.
Thus far, most focus has been on surging Texas production of what is known as condensate, a type of oil that is so light it often remains in gas form until it is pumped out of the ground. But a broader interpretation of the distillation process might allow other producers to export crude that has been minimally processed. (Reporting by Timothy Gardner and Kristen Hays in Houston)