Nitrox
Enriched Air Nitrox (EAN) is blends of gasses that are similar to normal air except they contain between 22% and 40% oxygen instead of 21%. The purpose of this is to all for longer bottom times in the mid-ranged depths. It is NOT safer than normal air. Either is safe if they are used correctly, so using it because it is assumed to be safer is an illusion.
Enriched Air Nitrox is a gas that has its benefits to the diving world, but it also has its dangers. There are special procedures that are associated with it, and therefor, no one should attempt to dive with EAN without having first received special training from a PADI Enriched Air Nitrox specialty instructor.
If you have further questions that you would like answered, feel free to send me an email.
Email: comptob@okstate.edu