Exclusion zones have been put in place around the Elgin platform in the North Sea, which has been suffering a serious gas leak since Sunday.
Coastguards said shipping was being ordered to keep at least two miles away and there was a three-mile exclusion zone for aircraft.
A cloud of gas was reported to be surrounding the platform, which is located 150 miles (240km) off Aberdeen.
Workers from a second platform and drilling rig have been removed.
Shell has moved 120 non-essential staff from the Shearwater platform and Hans Deul drilling rig, about four miles from the Elgin, because of the drifting gas.
Drill, baby, drill! If you want to destroy the world.