“I can say we tried. But what I can also say is this scares everybody, the fact that we can’t make this well stop flowing, or haven’t succeeded in that so far,” Doug Suttles, BP’s chief operating officer, said in a late-day news conference.

“There’s no silver bullet to stop this leak,” Coast Guard Rear Adm. Mary Landry said…

Sitting on the sea floor and awaiting deployment is a new containment dome, what the company calls the Lower Marine Riser Package cap. With robotic submarines, the company will sever the leaking, kinked riser pipe that emerges from the top of the blowout preventer, the five-story-tall contraption on top of the wellhead. Then engineers will guide the LMRP cap onto the pipe. The cap is fitted with a grommet designed to keep out seawater and prevent the formation of slushy methane hydrates that bedeviled an earlier containment dome effort. The cap procedure will take four to seven days, officials say.

“This operation should be able to capture most of the oil,” Suttles said. “I want to stress the word ‘most,’ because it’s not a tight, mechanical seal.”