At what partial pressure of oxygen does the risk of CNS toxicity significantly increase?

The risk of central nervous system (CNS) toxicity from oxygen exposure significantly increases at a partial pressure of oxygen of 1.6 atm. At this level, the likelihood of experiencing symptoms such as visual disturbances, convulsions, and other neurological effects escalates considerably.

This threshold is critical for divers using enriched air, as the partial pressure of oxygen in their gas mix can rise during deep dives or prolonged exposures, potentially leading to toxicity if levels are not monitored and managed carefully.

Understanding this threshold is crucial for safe diving practices, particularly when planning dives with nitrox mixtures. Staying below this limit helps ensure that divers minimize the risk of oxygen toxicity, allowing for safer exploration of underwater environments.