BP says it’s reached a ‘significant milestone’ after apparently controlling the oil leak in the Gulf of Mexico with its latest effort. The new operation employs a ‘static kill’ process which uses heavy mud to push the oil back down into the reservoir. The US government says 75 percent of the spill has now been cleaned up or broken down by nature. Around 700 million liters of oil’s gushed into the sea since a rig exploded in April causing what’s been branded as America’s worst environmental disaster.