A compressed gas cylinder safety cap and valve seal retainer comprising a cap having a floor, a wall and a stem, the wall extending perpendicularly from and circumferentially around the floor, the stem extending perpendicularly from the floor at the central axis of the floor; a second strap connected at its proximal end to the cap, the second strap having a pair of bendable areas, a tear tab and perforations, a second strap angled portion attached at its proximal end to the second strap and at its distal end to a clasp tab, the clasp tab having a double ridged portion extending perpendicularly away from the clasp tab, the double ridged portion having a first set of ridges and a second set of ridges offset from the first set of ridges; a first strap, the first strap being connected at its proximal end to the cap, the first strap having at its distal end a clasp receptacle, the clasp receptacle having a hollow interior, the hollow interior having mounted therein on an interior surface a series of ridges and on an opposite interior surface a biased armature, the clasp receptacle further having a proximal end opening and a distal end opening, the proximal end opening and the distal end opening being sized and shaped for the insertion therethrough of the clasp tab.