It's never been tried before, but crews hope to lower a 100-ton concrete-and-steel box a mile under the Gulf of Mexico on Thursday to cut off most of the hundreds of thousands of gallons of oil spewing from a blown-out well.
If it works, the system could collect as much as 85 percent of the oil that's been leaking from the ocean floor after the Deepwater Horizon rig exploded April 20, killing 11 workers.
"Hopefully, it will work better than they expect," first mate Douglas Peake told The Associated Press aboard the ship that brought the box to the site. The AP is the only news organization with access to the containment effort.
It won't solve the problem altogether. Crews are drilling a relief well to take the pressure off the blown-out well at the site, and that could take up to three months. Other possible solutions are also in the works.
More than 200,000 gallons of oil a day is pouring from the well, creating a massive sheen that's been floating on the Gulf for more than two weeks. As it moved closer to land, crews were frantically laying boom and taking other steps to prevent it from oozing into delicate coastal wetlands