What is a potential hazard of breathing pure oxygen at depth?

Breathing pure oxygen at depth can lead to acute oxygen toxicity, which is a significant concern for divers. At increased pressures, the partial pressure of oxygen rises, and this can result in toxic effects on the central nervous system. Symptoms may include visual disturbances, convulsions, and even loss of consciousness. These effects occur because the body's cells become overwhelmed by the high levels of oxygen, which can produce reactive oxygen species and lead to cellular damage.

The risk of oxygen toxicity increases significantly at depths greater than 30 feet (approximately 10 meters) when the partial pressure of oxygen goes beyond safe limits. This is why scuba divers using oxygen-enriched mixtures carefully manage their exposure to oxygen and ensure they do not exceed recommended limits at various depths. Understanding oxygen toxicity is crucial for safe diving practices, particularly when using gas mixtures that contain higher percentages of oxygen than air.