An apparatus (10b) includes an inflatable vehicle occupant protection device (14b). An inflation fluid source provides inflation fluid for inflating the protection device (14b). A structure (320) for supporting the protection device (14b) includes a vent opening (40b) for venting inflation fluid from the protection device. A vent member (300) is connectable to the structure (320) to block inflation fluid flow through the vent opening (40b). An actuatable device (120b) when actuated breaks the connection between the vent member (80b) and the structure (320) and moves the vent member away from the vent opening (40b) to permit inflation fluid venting. A flexible elongated member (350) has a first end (352) connected to the vent member (300) and a second end (354) connected to the structure (320). The member (350) secures the vent member (300) to the structure (320) after the connection between the vent member and the structure is broken.