Temporary oil cap removed in Gulf
Engineers have removed a temporary cap that stopped oil from gushing into the Gulf of Mexico from BP's blown-out well in mid-July.
More oil is not expected to leak into the sea, but crews are on standby with collection vessels just in case.
The cap was removed as a prelude to raising the massive piece of equipment underneath that failed to prevent the worst offshore oil spill in US history.
The government wants to replace the failed blow-out preventer first to deal with any pressure that is caused when a relief well BP has been drilling intersects the blown-out well.
Once that intersection occurs sometime after Labour Day, BP is expected to use mud and cement to plug the blown-out well for good from the bottom.
The rig explosion on April 20 killed 11 workers and led to 206 million gallons of oil spewing from BP's well.