BP oil spill from Deepwater Horizon spread over huge area of ocean floor

About two million barrels of oil from the BP spill off the US Gulf Coast in 2010 are believed to have settled on the ocean floor, according to a study.

What happened to two million of the nearly five million barrels from the Deepwater Horizon rig that gushed into the open waters was a mystery until now, said the findings on Monday in the Proceedings of the National Academy of Sciences journal.

Researchers analysed samples collected at more than 500 locations around the Macondo Well, where the leaked oil emerged, and found it had spread across the sea floor.

The oil was found to have moved over an area of 3,200 sqkm from the site, and might have gone even further.

"Our analysis suggests the oil initially was suspended in deep waters and then settled to the underlying sea floor," said the study by the University of California and the Woods Hole Oceanographic Institution in Massachusetts. Researchers came to this conclusion by studying sea-floor sediment cores for residual hopane, a hydrocarbon that comes from crude oil.

BP took issue with the findings and the method researchers used, saying the affected area was overestimated.