Which statement about Nitrox and decompression is true?

• A. Nitrox can extend bottom time for no-decompression dives and reduce decompression time
• B. Nitrox increases decompression time
• C. Nitrox eliminates all decompression risk
• D. Nitrox has no effect on decompression

Answer: (A)

Breathing nitrox changes inert gas loading by increasing the oxygen fraction and reducing nitrogen in the gas you breathe. With less nitrogen to saturate your tissues, you can stay at depth longer before you hit the no-decompression limit, and for profiles that would require decompression with air, the lighter inert gas load can shorten the decompression needed when you use a nitrox mix. The key constraint is oxygen exposure: the higher the oxygen fraction, the lower the maximum depth you can safely dive, to keep the partial pressure of oxygen within safe limits (the MOD). So the statement is true because nitrox can extend bottom time for no-decompression dives and can reduce decompression time, as long as you plan within safe PPO2 limits. It doesn’t remove all decompression risk, and results depend on depth, mix, and dive profile.