Spanners,
The air that I breath comes from the 12th stage of the HP comp. To get there it passes over the oil metering pump in the intake bullet. When engine a/icing is selected on, some of the 12th stage air is routed forward and then through small pipes inside the bullet before entering the LP comp and it occasionally induces oil out from the metering pump. This air/oil mix then ends up at the 12th stage and centifugal force throws it down the HP air outlets and it eventually gets up my nose. Then we have the cold air units with their syringe full of oil in the system as well.....
Id be more worried about your oxy mask that I hooped.