What gas is primarily used in mixed gas diving?

Mixed gas diving typically utilizes helium as a primary component when divers are operating at significant depths. This is because helium has several advantageous properties for deep diving. Unlike nitrogen, which can cause narcosis and is subjected to high pressure that increases the risk of decompression sickness, helium is much less narcotic and has a lower density, which helps to reduce the work of breathing at greater depths.

When mixed with oxygen, helium forms a breathing gas that allows divers to explore deeper environments safely while minimizing the physiological challenges associated with nitrogen. This is particularly important in technical diving and commercial diving operations where divers may be required to stay at depths for extended periods.

While oxygen is essential for life and is used in diving gases, its concentration must be carefully managed to avoid toxicity at high pressures. Nitrogen is typically present in most breathing gas mixtures but can lead to narcosis. Carbon dioxide, on the other hand, is a waste product of respiration and is not used as a breathing gas. The focus in mixed gas diving is on optimizing the mixture for safe and efficient breathing under high-pressure conditions.