History of decompression research and development gets too high when compared to the ambient pressure. These bubbles, and products of injury caused by the bubbles, can cause damage to tissues known as "decompression sickness" or "the bends". The immediate goal of controlled decompression is to avoid development of symptoms of bubble formation in the tissues of the diver, and the long-term goal is to also avoid complications due to sub-clinical decompression injury. The symptoms of decompression sickness are known to be caused by damage resulting from the formation and growth of bubbles of inert gas within the tissues and by blockage of arterial blood supply to
Investigation of diving accidents a gas may be toxic or insufficient to support consciousness if used at an inappropriate depth, and the inert gas components will not be correctly accounted for in decompression calculations, which might result in decompression sickness. Both oxygen toxicuty and hypoxia may render the diver unconscious without warning, and decompression sickness symptoms may be debilitating if severe, and are generally unexpected. Open circuit scuba is generally very reliable if correctly maintained and serviced, and tested before the dive. Maintenance and testing procedures are simple and few in number, nevertheless divers may neglect them due to complacency, distraction or incompetence. Rebreather