What is the recommended maximum partial pressure of oxygen for safe recreational diving?

The recommended maximum partial pressure of oxygen for safe recreational diving is 1.4 ATA (atmospheres absolute). This limit is established to minimize the risk of oxygen toxicity, which can lead to serious health issues, especially during deeper dives or longer durations. At a partial pressure of 1.4 ATA, the benefits of using enriched air nitrox for extending bottom time and enhancing safety during ascent can be realized while still maintaining a safe margin against the potential for oxygen toxicity.

Exceeding this partial pressure can increase the risk of central nervous system toxicity, which is characterized by symptoms like visual disturbances, convulsions, or impaired coordination. Staying at or below the 1.4 ATA limit while diving allows divers to take advantage of the increased nitrogen absorption benefits and reduced narcosis effects that nitrox provides, ensuring a safer diving experience overall.