An inflator device including a housing defining a storage chamber and a supply of gas generant material disposed within the storage chamber. The inflator device includes an initiator assembly having an initiator in actuating communication with the supply of gas generant material. A moisture barrier member is disposed between the initiator assembly and the supply of gas generant material. The moisture barrier member acts to prevent moisture transmission from the initiator assembly to the supply of gas generant material. Upon actuation of the initiator, however, the moisture barrier member ruptures to permit reaction initiating communication between the initiator and at least a portion of the supply of gas generant material contained within the inflator device.