The US coast guard says it will set fire to a massive oil spill in the Gulf of Mexico.
There are fears the spill could become one of the worst in US history.
"This oil will then be towed to a more remote area, where it will be ignited and burned in a controlled manner," a statement said.
The slick covers an area 48 miles long and 39 miles wide, close to the Mississippi Delta.
Attempts to seal the leaking well using robot submarines operating some 1,500m (5,000ft) down on the ocean floor have so far failed.
The huge slick is now threatening the coast of Louisiana.
The Deepwater Horizon rig caught fire and collapsed killing 11 workers
There are fears a shift in winds could push it inland this weekend.
Rear Admiral Mary Landry said: "I am going to say right up front, the BP efforts to secure the blow-out preventer have not yet been successful.
"If we don't secure the well, yes, this will be one of the most significant oil spills in US history."
BP, which leases the site known as the Deepwater Horizonplatform, says an estimated 42,000 gallons of oil is leaking into the Gulf of Mexico every day after the rig caught fire and sank last week, killing 11 workers.
