What is a 'safety stop' in diving, and what is its purpose?

A 'safety stop' in diving refers to a brief pause at a shallower depth, typically around 15 to 20 feet (5 to 6 meters), during the ascent from deeper depths. The primary purpose of this pause is to allow for the off-gassing of nitrogen that has accumulated in the body while diving. As divers descend, they are exposed to higher pressures that increase the amount of nitrogen dissolved in their body tissues. When ascending, this pressure decreases, and the nitrogen must be expelled safely to minimize the risk of decompression sickness, commonly known as "the bends."

By incorporating a safety stop, divers can give their bodies time to release this excess nitrogen gradually, significantly reducing the chance of bubbles forming in the tissues or bloodstream as they return to the surface. This practice is an essential safety measure in diving, promoting a safer ascent and enhancing diver health and safety.

The other options touch on various aspects of diving but do not pertain to the defined role of a safety stop in decompression practices and physiological safety.