Abstract: The present invention comprises, in one embodiment, a compression safety valve apparatus adapted to engagingly connect to an existing gas cylinder valve. In one embodiment, the present invention comprises a housing base having a first bore, a rupture disc holding means having a second bore, at least one rupture disk, a piston having at least a third bore, a spring, and an outer housing cylinder having a forth bore, the first bore, the second bore and the third bore all being in gas flow communication with the compressed content of the tank. In operation, for example, during an over-pressurization event occurs, the extreme force of the escaping gas places a force on the bottom surface of the present invention's rupture disc assembly, so that the piston's beveled surface substantially mechanically engages the outer housing's upper ceiling. This mechanical engagement allows gas to continue to escape from the tank through one or more bleeder bores and a gap.