What is the primary risk associated with exceeding the partial pressure of oxygen limits?

The primary risk associated with exceeding the partial pressure of oxygen limits is central nervous system oxygen toxicity. When divers breathe oxygen at higher pressures, the partial pressure of oxygen increases. This increased pressure can lead to harmful effects on the central nervous system, including symptoms such as visual disturbances, muscle twitching, seizures, and other neurological impairments.

Central nervous system oxygen toxicity occurs when the partial pressure of oxygen rises beyond safe levels, typically around 1.6 ATA (atmospheres absolute) for recreational divers breathing oxygen. It is crucial for divers to monitor the partial pressure of oxygen in their breathing gas to prevent these potentially life-threatening neurological effects.

In contrast, decompression sickness is related to the formation of nitrogen bubbles during rapid ascent after a dive, barotrauma involves injuries caused by pressure changes, and carbon monoxide poisoning results from exposure to carbon monoxide gas, not from the pressures involved in diving. Understanding these distinctions is essential for safe diving practices.