What is the recommended action if a diver cannot shift to oxygen at 30' or 20'?

The recommended action of continuing decompression in water on air is grounded in the principles of dive safety and physiology. When a diver has not successfully completed the switch to oxygen at the prescribed depths of 30 feet or 20 feet, it indicates a potential issue with the diver’s gas management or equipment performance.

Continuing with air during decompression allows the diver to complete the ascent in a controlled manner while minimizing the risk of rapid ascent, which can lead to decompression sickness (DCS). Staying at the appropriate depth and completing the necessary stops while on air provides the body time to off-gas nitrogen safely.

Aborting the dive or signaling for a surface rescue might introduce unnecessary risk, especially if the diver is still capable of managing the situation in the water. Initiating emergency ascent procedures could also lead to complications due to the increased likelihood of rapid ascent scenarios where the risk of DCS is heightened.

Thus, continuing to decompress on air aligns with the safest practices for divers in distress, promoting a methodical approach to resolving the issue at hand while safeguarding the diver's health.