A system of preventing any explosion in the cargo tanks of a tanker by replacing the cargo, as it is pumped out, by an inert gas, sometimes by flue gas from ship boilers. Gas freeing must be carried out subsequently if workers have to enter the empty tanks.
Further reading: IMO Guidelines for Inert Gas Systems, ABS Guide for Inert Gas System For Ballast Tanks can be downloaded from www.eagle.org.
