The mixtures typically use either USP aviation oxygen or USP medical oxygen. Both are of the highest quality and the only difference is that aviation oxygen has less water vapor so it does not freeze at high altitudes.
When using mixtures with higher amounts of oxygen, you need to be aware of safety requirements.
Oxygen is not compatible with oils, gasoline, or other petroleum products. It is highly flammable under pressure in the presence of hydrocarbons, silicone vapors, and other impurities.
All equipment associated with the use of mixtures containing more than 40% oxygen requires so-called oxygen cleaning and must have special lubrication and seals.
Cylinders, valves, gauges and regulators used for mixtures Nitrox with an oxygen content of 40% or more must be made of oxygen-compatible materials and be regularly oxygen-cleaned. Oxygen-cleaned equipment is labeled “Oxygen Only” and cannot be used with air.
Equipment should only be inspected and cleaned by a certified technician.
Cylinders and valves for the use of NITROX mixtures containing less than 40% oxygen require oxygen cleaning only if the mixture is prepared in them by adding oxygen with high pressure air.