An inflatable separation device and method of using the device to form a gas-impermeable barrier in a structural location such as a hallway. The device also provides a safe, effective passage across the barrier to form a concealed region for decontamination protocols. The inflatable separation device includes an inflatable support frame and a cover that envelops the support frame and forms an enclosed interior space when the support frame is inflated. An inflatable perimeter sealing bladder is disposed about the cover and adapted to form a seal between the cover and exterior surfaces of a structural space when the support frame and the sealing bladder are inflated.