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

The maximum allowable partial pressure of oxygen for recreational diving is 1.4 ATA (atmospheres absolute). This limit is established to help prevent oxygen toxicity, which can occur when divers breathe higher levels of oxygen under pressure.

At 1.4 ATA, the risk of central nervous system oxygen toxicity increases, especially during deeper dives. Recreational diving guidelines recommend this limit to ensure diver safety while enjoying the benefits of enriched air Nitrox, which contains a higher percentage of oxygen than regular air. Such a threshold allows divers to gain the advantages of reduced nitrogen levels in their breathing gas while minimizing the risk associated with excessive oxygen exposure.

Maintaining the partial pressure of oxygen at or below this limit is crucial for safe diving practices, particularly during deep or extended dives where the cumulative exposure to oxygen at increased pressures can pose health risks.