Oxygen toxicity in recreational and technical diving

It is increasingly common for recreational scuba divers to use breathing mixtures enriched with additional oxygen ('nitrox' or 'enriched air nitrogen') and for technical divers to be exposed to elevated partial pressures of oxygen for prolonged periods of time. The National Oceanic and Atmospheric Administration oxygen exposure limits have traditionally been used by the recreational diving industry and technical diving communities. Review of the original research into oxygen toxicity brings into question the validity of these limits and would suggest revised limits with a maximum partial pressure of oxygen of 162 kPa (1.6 Ata) and 142 kPa (1.4 Ata) at depth and the use of the repetitive air excursion (REPEX) limits for single and repetitive exposures. Suitable conservatism in case of the need for recompression therapy is recommended.