Editing Decompression sickness (section)

=== Inert gases ===
The main inert gas in air is [[nitrogen]], but nitrogen is not the only gas that can cause DCS. [[Breathing gas]] mixtures such as [[Trimix (breathing gas)|trimix]] and [[heliox]] include [[helium]], which can also cause decompression sickness. Helium both enters and leaves the body faster than nitrogen, so different decompression schedules are required, but, since helium does not cause [[Nitrogen narcosis|narcosis]], it is preferred over nitrogen in gas mixtures for deep diving.{{sfn|Hamilton & Thalmann|p=475}}
There is some debate as to the decompression requirements for helium during short-duration dives. Most divers do longer decompressions; however, some groups like the [[WKPP]] have been experimenting with the use of shorter decompression times by including [[Decompression practice#Deep stops|deep stops]].{{r|Wienke2002}} The balance of evidence as of 2020 does not indicate that deep stops increase decompression efficiency.<!-- Several sources, Mitchell? Doolette and Mitchell? -->

Any inert gas that is breathed under pressure can form bubbles when the ambient pressure decreases. Very deep dives have been made using [[hydrogen]]–oxygen mixtures ([[Hydrox (breathing gas)|hydrox]]),{{r|fife}} but controlled decompression is still required to avoid DCS.{{r|uhms33}}