History of decompression research and development range of commercial, military and recreational diving. The first recorded experimental work related to decompression was conducted by Robert Boyle, who subjected experimental animals to reduced ambient pressure by use of a primitive vacuum pump. In the earliest experiments the subjects died from asphyxiation, 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 pressurisation of mines and caissons to exclude water ingress, miners were observed to present symptoms of what would become known as caisson disease, the bends, and decompression sickness. Once it was
Scuba set or use lower proportions of oxygen than air. In these situations divers often carry additional scuba sets, called stages, with gas mixtures with higher levels of oxygen that are primarily used to reduce decompression time in staged decompression diving. These gas mixes allow longer dives, better management of the risks of decompression sickness, oxygen toxicity or lack of oxygen (hypoxia), and the severity of nitrogen narcosis. Closed circuit scuba sets (rebreathers) provide a gas mix that is controlled to optimise the mix for the actual depth at the time. Gas cylinders used for scuba diving come in various sizes and