WASHINGTON, Feb 6 (Reuters) - Marathon Petroleum Corp has begun returning oil to the U.S. petroleum stockpile known as the Strategic Petroleum Reserve, months after receiving an emergency loan in response to Hurricane Isaac in 2012.

The U.S. Energy Department released 1 million barrels of crude from the SPR in August after Hurricane Isaac, a slow moving storm that targeted parts of the Gulf of Mexico, slowed output from one of Marathon's refineries.

The stockpile currently stands at about 695.8 million barrels, up from around 694.95 million on Jan. 4.

The department confirmed the increase was due to the exchange with Marathon.

Created in the 1970s after the Arab oil embargo, the reserve can hold 727 million barrels of oil at full capacity.

(Reporting by Ayesha Rascoe; Editing by David Gregorio) Keywords: USA SPR/EXCHANGE MARATHON

(ayesha.rascoe@thomsonreuters.com)(Twitter @ayesharascoe)(202-310-5683)(Reuters Messaging: ayesha.rascoe.thomsonreuters.com@reuters.net)

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