What is the risk when a diver exceeds the MOD while diving with Nitrox?

Exceeding the Maximum Operating Depth (MOD) while diving with Nitrox presents a significant risk of oxygen toxicity. Nitrox is a gas mixture that typically has a higher percentage of oxygen than air, and while this can beneficially reduce the risk of nitrogen narcosis and improve air supply at shallower depths, it also increases the partial pressure of oxygen as depth increases.

When a diver descends beyond the MOD, the partial pressure of oxygen in the breathing gas becomes elevated to the point where it can lead to oxygen toxicity. This condition manifests in two forms: central nervous system (CNS) toxicity, which can cause symptoms such as visual disturbances, seizures, and convulsions, and pulmonary toxicity, which can lead to respiratory issues over time.

Understanding the risk of oxygen toxicity is crucial for divers using Nitrox because it helps them make informed decisions regarding their dive profiles and adhere to safety protocols to avoid potentially life-threatening situations. Proper planning and adherence to MOD guidelines are essential to ensure a safe diving experience.