What is the fourth step of the gas switching procedure?

The fourth step of the gas switching procedure involves turning on the decompression cylinder and orientating the regulator. This step is crucial because, during a dive, especially at depth, divers may need to switch to a different gas mixture that is more suitable for the conditions they are encountering or for the decompression schedule they are following.

Turning on the decompression cylinder ensures that the diver has immediate access to the correct gas when needed. Additionally, orientating the regulator is essential for ensuring that it delivers the gas efficiently and correctly, preventing any potential issues with airflow or accessibility during a critical moment. Properly managing gas supplies is vital for safety during decompression, as it minimizes the risk of hypoxia or nitrogen narcosis, both of which could arise if the gas switch is not executed correctly.

While checking oxygen levels, inspecting the dive site, and communicating with a buddy are all important parts of a safe dive, they each play a different role and are generally addressed earlier in the dive preparation or safety protocols.