Abstract: The present invention resides in a vehicle occupant restraint assembly (12). The assembly comprises a vehicle occupant restraint (20), a housing (14), a gas generating composition (16) within the housing, an igniter (18) for igniting the gas generating composition, and gas flow means (22) for directing gas into the vehicle occupant restraint. In a preferred embodiment of the present invention, the vehicle occupant restraint (20) is an air bag. The gas generating composition (16) comprises lithium azide (Li.sub.3 N) and a metal oxidant (MeO), wherein O can be either oxygen or sulfur. The metal oxidant is present in a sub-stoichiometric amount relative to the lithium azide. The gas generating composition (16), on ignition, burns under reaction conditions which produce lithium nitride (Li.sub.3 N) and a combustion product which is essentially free of elemental lithium.