Abstract: The disclosed device primarily consists of a band, ring, or other piece of shape memory polymer (SMP) or SMP composite in various embodiments that allows or disallows containment. When the SMP reaches its transition temperature (Tg) the SMP provides the means for releasing containment of the pressurized material so as to prevent ignition or explosion of hazardous material. At normal operating temperatures, the SMP is in a deformed shape maintaining an environmental seal to protect the contents of the container. When environmental conditions cause the SMP or SMP composite to exceed its Tg, specified by the operating requirements, the SMP returns to its memory shape in a controlled geometry, rather than simply melting. The return of the SMP to its memory shape causes the venting of the container in different manners depending on which embodiment is utilized.