If a diver exceeds the maximum recommended depth for a Nitrox mix, what are they risking?

When a diver exceeds the maximum recommended depth for a Nitrox mix, the primary risk they face is oxygen toxicity and rapid decompression issues. Nitrox, which is a gas mixture that contains a higher percentage of oxygen than regular air, has certain depth limits based on the percentage of oxygen in the mix. As a diver descends, the partial pressure of oxygen increases, which can lead to toxic effects on the central nervous system. Symptoms of oxygen toxicity can include visual distortions, nausea, twitching, and even convulsions, which can be quite dangerous underwater.

Additionally, if a diver ascends too quickly after exceeding the depth limit, they may experience rapid decompression. This can lead to decompression sickness, also known as "the bends," which occurs when nitrogen bubbles form in the body due to a rapid decrease in pressure. Adhering to the maximum depth recommendations for any Nitrox mix is crucial to avoid these serious risks and ensure the diver's safety.

Other choices do not accurately reflect the risks associated with exceeding depth limits. Increased buoyancy is not a concern linked directly to depth; improved visibility and better nitrogen absorption are generally not consequences of exceeding maximum depth, making them unsuitable answers in this context.