A wellhead severing system for detonating a liquid explosive charge and subsequent removal of the wellhead from the sea floor. The explosive severing system includes a charge container holding a liquid explosive and a contractable bladder in fluid communication with the charge container to compensate for pressure and temperature variations as the system is lowered to the wellhead in the sea floor. Liquid explosive from the bladder flows into the charge container maintaining a constant volume of uncontaminated explosive around the detonators. The severing system is lowered into the wellhead on a running string and detonated through high voltage wires extending to a connector or the surface.