Blown-out BP oil well finally sealed

A cement plug has permanently killed BP's runaway well nearly 2.5 miles below the sea floor in the Gulf of Mexico - five months after an explosion sank a drilling rig and led to the worst offshore oil spill in US history.

Retired Coast Guard Admiral Thad Allen, the federal government's point man on the disaster, said that BP's well "is effectively dead" and posed no further threat to the Gulf.

Allen said a pressure test to ensure the cement plug would hold was completed successfully.

President Barack Obama called the successful "kill" a milestone in his administration's response to the disaster that leaked hundreds of millions of gallons of oil.

In a statement he said that his administration remains committed to doing everything possible to ensure that the Gulf Coast recovers fully from the disaster.

Obama pledged that his administration will continue to work closely with people who live in the Gulf region as they rebuild their livelihoods and restore the environment.

The gusher was contained in mid-July after a temporary cap was successfully fitted atop the well. Mud and cement were later pushed down through the top of the well, allowing the cap to be removed.

But the well could not be declared dead until a relief well was drilled so that the ruptured well could be sealed from the bottom, ensuring it never causes a problem again. The relief well intersected the blown-out well on Thursday, and crews started pumping in the cement on Friday.

The April 20 blast killed 11 workers, and 206 million gallons.

The disaster caused an environmental and economic nightmare for people who live, work and play along hundreds of miles of Gulf shoreline from Florida to Texas. It also spurred civil and criminal investigations, cost gaffe-prone BP chief Tony Hayward his job, and brought increased governmental scrutiny of the oil and gas industry, including a costly moratorium on deepwater offshore drilling that is still in place.