What is the minimum requirement for oxygen periods if a diver was on oxygen during an omitted decompression?

The correct answer reflects the standard practice in diving medicine regarding oxygen therapy following omitted decompression. If a diver has omitted decompression and is provided with supplementary oxygen, the minimum requirement for oxygen therapy is defined to mitigate the risk of decompression sickness (DCS).

Specifically, during an omitted decompression scenario, one half period—such as 15 minutes at 50 feet of seawater—is typically recommended as it helps to reduce the nitrogen load in the body and assists in off-gassing nitrogen more efficiently. This period allows the body to eliminate excess nitrogen absorbed during the dive, which is crucial for preventing DCS. Therefore, adhering to this guideline ensures that divers receive adequate treatment while minimizing the potential for complications associated with omitted decompression.

In contrast, simply having one full period of oxygen therapy or two periods may not be necessary based on the specific context or the risks involved in the situation, and stating no minimum requirement does not align with established safe diving practices.