PADI Divemaster Certification Practice Exam

What is a major concern when supervising enriched air dives?

1. Oxygen toxicity

2. Drowning

3. Fire hazard

4. Planning for decreased no stop time

The correct answer is: Oxygen toxicity

In the context of supervising enriched air dives, a major concern is oxygen toxicity. Enriched air, or nitrox, contains a higher concentration of oxygen than air and reduces the amount of nitrogen. While this type of diving can extend bottom times and lower nitrogen absorption, the increased oxygen levels can also lead to central nervous system toxicity, particularly if divers exceed recommended partial pressures of oxygen. When divers breathe higher concentrations of oxygen, especially at deeper depths, there is a risk of experiencing symptoms such as visual disturbances, twitching, or even convulsions, which can severely impair the diver's ability to react and may lead to dangerous situations underwater. Supervisors must be aware of these risks and ensure that divers are educated on the appropriate maximum depths and exposure times to manage this hazard effectively. The other concerns mentioned, such as drowning or fire hazards, while relevant to diving safety in general, are not specific to enriched air diving. Planning for decreased no stop time, although important in dive planning, is a practical concern rather than a safety concern associated with the physiological effects of breathing enriched air.