BP has begun implementing its latest plan to plug the leaking oil pipe in the Gulf of Mexico, Interior Secretary Ken Salazar said early this afternoon. The "top kill" plan involves pumping up to 50,000 pounds of artificial, heavy "mud" into the leaking oil pipe in the Gulf of Mexico and then sealing the pipe with cement. It will still be a day or two before the outcome is known, BP's CEO Tony Hayward said. He has given it a 60 to 70 percent chance of success.
The oil leak began shortly after an April 20 explosion on an offshore, oil rig BP was using. The initial response hinged largely on the use of chemical dispersants -- a toxic solution to a toxic problem -- which would effectively break up the growing slick and make the oil more water-soluble, dropping it below the surface.
Within days of the explosion, 100,000 gallons of chemicals were flown to three Gulf Coast locations as a precaution, according to an early Associated Press blow-by-blow. Concerns mounted and the Environmental Protection Agency at one point forced BP to stop the effort, pending test results. BP eventually continued and has dropped 815,000 gallons of dispersant in total, but the head of the EPA recently asked BP to cut back.
The Relief Well
Of course, dispersants won't do anything to stop the leak. On May 2, BP began drilling the first of two relief wells, into which BP would pump heavy fluid to prevent more oil from leaking, enabling the company to plug the pipe with cement. BP has begun work on the second relief well, too, but neither will be completed until August. (Click the image below to view BP's diagram of the effort.)
The Containment Box
On Saturday, May 8, the company tried to lower a 100-ton, four-story containment box over the leak to serve as an upside-down funnel. The effort failed when the box was unsurprisingly clogged:
Company and Coast Guard officials had cautioned that icelike hydrates, a slushy mixture of gas and water, would be one of the biggest challenges to the containment box plan, and their warnings proved accurate. The crystals clogged the opening in the top of the peaked box like sand in a funnel, only upside-down.
After the failure of the containment box, BP considered a similar attempt with a smaller dome dubbed a "top hat." But the company abandoned that idea before even trying it for yet another option: the Riser Insertion Tube. This was pretty simple: A small tube with large rubber "diaphragms" was inserted into the pipe. Oil was siphoned through the tube and the rubber "diaphragms" served to reduce leakage. According to BP, the Riser tube succeeded in siphoning off over one-fifth of the leaking oil. (Here's BP's official diagram of how the Riser tube works.)