Narcosis while diving (also known as nitrogen narcosis, inert gas narcosis, raptures of the deep, Martini effect), is a reversible alteration in consciousness that occurs while diving at depth. It is caused by the anesthetic effect of certain gases at high pressure. The Greek word Î˝Î±ĎÎşĎ‰ĎƒÎąĎ‚ (narcosis) is derived from narke, "temporary decline or loss of senses and movement, numbness", a term used by Homer and Hippocrates.Askitopoulou2010 Narcosis produces a state similar to drunkenness (alcohol intoxication), or nitrous oxide inhalation. It can occur during shallow dives, but does not usually become noticeable at depths less than 30|m|ft|sigfig=1|sp=us. Except for helium and probably neon, all gases that can be breathed have a narcotic effect, although widely varying in degree.Bennett|Rostain|2003|p=305Bauer1970 The effect is consistently greater for gases with a higher lipid solubility, and there is good evidence that the two properties are mechanistically related.Bennett|Rostain|2003|p=305 As depth increases, the mental impairment may become hazardous. Divers can learn to cope with some of the effects of narcosis, but it is impossible to develop a tolerance. Narcosis affects all divers, although susceptibility varies widely from dive to dive, and between individuals. Narcosis may be completely reversed in a few minutes by ascending to a shallower depth, with no long-term effects. Thus narcosis while diving in open water rarely develops into a serious problem as long as the divers are aware of its symptoms, and are able to ascend to manage it. Diving beyond 40|m|ft|abbr=on is generally considered outside the scope of recreational diving. Below these depths, as narcosis and oxygen toxicity become critical risk factors, specialist training is required in the use of various helium-containing gas mixtures such as trimix or heliox. These mixtures prevent narcosis by replacing some of the breathing gas with non-narcotic helium. 2. (An OSH glossary used in safety and health at work which is, adopted by ILO {102}.. The term definition has been obtained from the secondary source