Oxygen

Oxygen is the necessary, life supporting, part of air. Without Oxygen you die. However, too much oxygen in your tank can also cause problems, because oxygen becomes toxic at depth.

As divers, there are two types of Oxygen toxicity that we must consider --- Central Nervous System Oxygen Toxicity and Pulmonary Oxygen Toxicity.

Central Nervous System (CNS) Oxygen Toxicity is the toxic effect on the brain of breathing high Oxygen concentration mixtures for too long a time period.

Signs and symptoms of CNS Oxygen Toxicity may be any of the following --- visual disturbances, ringing in the ears, nausea, muscular twitching, irritability, dizziness, and convulsions. It is important to note that these signs and symptoms do not proceed in any particular order i.e. convulsions and subsequently death by drowning, can occur without warning.

Clearly, the proper course of action regarding CNS Oxygen Toxicity is prevention. Never exceed the Maximum Operating Depth of the mix.

Warning

In no case should your planned or actual dive ever exceed the maximum Oxygen pressure of 1.6 AtA.

For prolonged, or strenuous, or cold water dives, limit the maximum Oxygen pressure to 1.4 AtA.

Pulmonary Oxygen Toxicity is the toxic effect on the lungs of breathing high Oxygen concentration mixtures for too long a time period.

Signs and symptoms of Pulmonary Oxygen Toxicity may be any of the following --- shortness of breath, dry coughing, lung irritation, a burning sensation in the breathing cycle, and a reduction in lung vital capacity. Complete recovery usually occurs within a few days.

Pulmonary Oxygen Toxicity is normally not a problem for technical divers because the dose/time levels required are much higher than those experienced on technical dives.

For additional information on Oxygen Toxicity see the Appendix - NOAA Diving Manual Excerpts on Oxygen Poisoning.

Physiology of Diving Gasses
Oxygen
Self Test

The signs and symptoms of CNS Oxygen Toxicity may be any of the following --- visual disturbances, ringing in the ears, nausea, muscular twitching, irritability, dizziness, and convulsions.

In no case should your planned or actual dive ever exceed the maximum Oxygen pressure of ____ .

For prolonged, or strenuous, or cold water dives, limit the maximum Oxygen pressure to ____ .

The signs and symptoms of Pulmonary Oxygen Toxicity may be any of the following --- shortness of breath, dry coughing, lung irritation, a burning sensation in the breathing cycle, and a reduction in lung vital capacity.

Pulmonary Oxygen Toxicity is normally not a problem for technical divers because the dose/time levels required are much higher than those experienced on technical dives.