An apparatus and method for gaining access to the contents of pressurized vessels and systems and for discharging the contents safely under controlled conditions. The apparatus, comprised essentially of a ball valve and pressure tube assembly having a coaxial conduit in which is mounted for longitudinal movement a rotatable shaft and drill bit, is connected to the pressurized vessel. The rotatable shaft in the preferred embodiment is provided with fluid conducting means so that when communication with the contents of the vessel is made, pressure on both ends of the shaft is equalized. At this point, the ball valve is shut off, the pressure tube assembly, shaft and drill bit are removed, and a hose or other take-off device is connected to the ball valve for safe disposal of the contents of the pressurized vessel.