Nearly 75% of spilled oil gone

Nearly 75% of the oil that spilled into the Gulf of Mexico following a tragic explosion on BP Plc's Deepwater Horizon rig is now gone, a release issued by the White House said.

One third of that oil was removed via human effort, which included burning, skimming, and chemical dispersion. Another 41% evaporated, dissolved, or dispersed itself naturally, according to a federal science report.

That means just over a quarter of all oil spilled, roughly 26%, remains in the Gulf. And that oil is either on or just below the water's surface, or has washed ashore on to beaches, the report said.

An estimated 4.9 million barrels of oil leaked into the Gulf, the report said, which means roughly 1.2 million barrels of oil remain in Gulf waters and surrounding areas.

Jane Lubchenco, an administrator with the National Oceanic and Atmospheric Administration, said that while the threat of damage caused by oil persists to a degree, the new information will help relief efforts.

“Less oil on the surface does not mean that there isn't oil still in the water column or that our beaches and marshes aren't still at risk,” Lubchenco said, adding that, “Knowing generally what happened to the oil helps us better understand areas of risk and likely impacts.”