A systematic study of the principles of a novel airbag inflator type, the‘Stored Liquefied Gas Inflator’,was performed by means of tank tests and high-speed cinematography. The new inflator is intended primarily for side-impact airbags and is based on the rapid flashing of liquefied CO2 . The new approach leads to a simple, inexpensive, environmentally attractive and safe device. Experiments were performed at different initial vessel and tank conditions and allowed the identification of the dominant physical phenomena in the components of the system, the definition of the design parameters, and the assessment of the performance. The optimal storage pressure was determined and the inflator’s behavior was observed to depend strongly on ambient temperature. The addition of small amounts of various organic liquids to the liquefied CO2 to a significant increase in performance. The potential of the novel inflator was assessed and suggestions to increase its performance were formulated.