What is the maximum PPO2 limit generally accepted for recreational diving?

The maximum partial pressure of oxygen (PPO2) limit generally accepted for recreational diving is 1.4 ATA. This limit is established to minimize the risk of oxygen toxicity, which can become a concern when divers breathe higher concentrations of oxygen under pressure. At 1.4 ATA, the oxygen partial pressure is still within a safe range for most recreational diving activities, allowing divers to benefit from increased oxygen availability while reducing the likelihood of adverse effects.

Using a PPO2 beyond this level, particularly at pressures higher than 1.4 ATA, significantly increases the risk of central nervous system toxicity, which can manifest as seizures or other symptoms that can endanger divers. Consequently, this limit provides a balance between enhancing safety and optimizing performance during dives.