By DAN MURTAUGH

The dam holding back US crude exports is cracking.

Petroleos Mexicanos, the state-owned oil company in Mexico, announced it has received a license from the US government to import as much as 75,000 bpd of American crude. It’s the first time the US has given such a license to a country other than Canada in 40 years.

Pemex’s PMI unit will import light crude for one year starting in October in exchange for heavy Mexican oil, the company said in an e-mailed statement. The lighter grades will help the nation’s refineries produce more cleaner fuels, the company said.

“Among the benefits expected from this exchange of oil are integrating energy markets in North America, strengthening trade relations between Mexico and the US, improving logistics by reducing transportation costs through shipping efficiency to Mexico, and maximizing refining margins,” the company said in its statement.

Energy producers including ExxonMobil and ConocoPhillips have called for an end to rules restricting US crude exports that were instituted after the Arab oil embargo in the 1970s. The US House of Representatives passed a bill repealing the restrictions earlier this month, while lacking the votes to override a threatened presidential veto by the Obama administration.

Drilling in shale regions from Texas to North Dakota reversed a decades-long decline in US oil production. Much of the new output sells at a discount to global prices for a number of factors, including that it’s mostly trapped within the US by the export rules.

The US has a few exceptions to its crude export rules. Shipments to Canada are allowed, for example, and the Commerce Department last year ruled that exports of lightly processed condensate, an ultra-light form of oil found in some shale rock, can be sent abroad. Commerce officials approved the swap with Mexico earlier this year.

Pemex lost money for the 12th straight quarter, the company said today. It lost 167.6 billion pesos ($10.18 billion) in the third quarter compared with a 60 billion-peso shortfall a year earlier as oil prices and output fell.

Pemex has said the US crude will help boost gasoline production at its refineries in Salamanca, Tula and Salina Cruz. Pemex exported 803,000 bpd of mostly heavy oil to the US last year, and Mexico imports about half its gasoline. Crude output from Pemex has been falling for a decade.

Mexico’s government approved energy reforms last year that allowed its refiners to import oil, after decades of relying on its own production.