What is the primary concern when diving with higher oxygen concentrations?

When diving with higher oxygen concentrations, the primary concern is the risk of oxygen toxicity. As the partial pressure of oxygen increases, especially at depths greater than approximately 1.4 ATA (atmospheres absolute), the likelihood of experiencing oxygen toxicity rises. This condition can lead to a range of serious health issues, including convulsions, visual disturbances, and other neurological effects.

Oxygen toxicity is particularly critical to monitor because it can occur more quickly in deeper dives where the pressure increases the partial pressure of oxygen in the breathing gas. Divers using enriched air nitrox must be trained to recognize their depth limits and understand how to manage their oxygen exposure throughout their dive.

While decompression sickness, reduced visibility, and increased air consumption are important factors in the overall safety of diving, they do not pose the same immediate and severe threat that oxygen toxicity does when using oxygen-rich mixtures like nitrox. Thus, it is essential for divers to be aware of and manage the risks associated with elevated oxygen levels to ensure a safe diving experience.