The US Coast Guard says oil is now leaking from a well underneath a drilling rig that exploded and sank into the Gulf of Mexico.
An estimated 1000 barrels per day is coming from the well 1525 metres beneath the surface of the ocean.
The Coast Guard calls it a "very serious spill."
The Deepwater Horizon rig sank 68km off the coast of Louisiana on Thursday following an explosion on Tuesday night.
A search for 11 missing workers from the rig, who are presumed dead, has been suspended.