What is the maximum recommended depth for using 100 percent oxygen?

The correct answer indicates that the maximum recommended depth for using 100 percent oxygen is 20 feet. At this depth, the partial pressure of oxygen remains within safe limits for recreational diving. Breathing pure oxygen at depths greater than this can lead to oxygen toxicity, as the partial pressure of oxygen increases with depth.

When divers breathe oxygen under increased pressure, it can reach levels that are toxic to the central nervous system, potentially leading to symptoms like seizures or other serious side effects. Thus, the recommendation to limit the depth to 20 feet helps ensure that divers avoid exceeding safe exposures to oxygen while utilizing 100 percent oxygen in their diving activities.

In contrast, the other depths listed here are below this threshold, which makes them seem safer; however, the established maximum often cited in the diving community is specifically around 20 feet due to the risks associated with depth and pure oxygen. Therefore, understanding these limits is crucial for safe diving practices.