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1.1.3. NITROX
Diving with nitrox provides the diver with an opportunity to reduce the risk of
decompression illness by reducing the nitrogen content in the breathing gas mix.
However, when the gas mix is altered, the oxygen content of the mix is generally
increased. This increase exposes the diver to an oxygen toxicity risk not usually
considered in recreational diving. In order to manage this risk, the dive computer
tracks the time and intensity of the oxygen exposure and provides the diver with
information to adjust the dive plan in order to maintain oxygen exposure within
reasonably safe limits.
In addition to the physiological effects of enriched air on the body there are
operational considerations to be addressed when handling altered breathing mixes.
Elevated concentrations of oxygen present a fi re or explosion hazard. Consult with
the manufacturer of your equipment about its compatibility with nitrox.
1.1.4. FREEDIVING
Freediving, and particularly freediving in combination with scuba diving, may
have risks that have not been researched and are not commonly known.
Any person who engages in any form of breathhold diving is in danger of shallow-
water blackout (SWB) i.e. the sudden loss of consciousness caused by oxygen
starvation.
Any breathhold diving results in some nitrogen build-up in the blood and other
fast tissues. Due to the short time spent at depth this build-up is generally not
signifi cant. Therefore, provided the effort involved in freediving has not been
