BP called the achievement “a significant milestone” and said it stopped pumping mud into the well after about eight hours because the effort had been successful…

Federal officials huddled in BP’s operations center are trying to manage expectations, saying that even if the static kill goes as hoped, the well at the bottom of the Gulf of Mexico won’t be kaput until it is intercepted and cemented by a relief well that’s been three months in the drilling.

“You want to make sure it’s really dead dead dead. Don’t want anything to rise out of the grave,” Energy Secretary Steven Chu told The Washington Post late Tuesday afternoon.