Decompression (diving) but in later experiments signs of what was later to become known as decompression sickness were observed. Later, when technological advances allowed the use of pressurization of mines and caissons to exclude water ingress, miners were observed to present symptoms of what would become known as caisson disease, compressed air illness, the bends, and decompression sickness. Once it was recognized that the symptoms were caused by gas bubbles, and that re-compression could relieve the symptoms, Paul Bert showed in 1878 that decompression sickness is caused by nitrogen bubbles released from tissues and blood during or after decompression, and showed the
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