Final answer:
A warning device on an SCBA that alerts when the breathing air is nearly depleted is called a Low-air indicator. Divers use tank gauges to monitor their air supply and prevent running out of air which could lead to decompression sickness, a serious condition requiring careful ascent procedures and possible hyperbaric oxygen therapy.
Step-by-step explanation:
The warning device on an SCBA (Self-Contained Breathing Apparatus) that alerts the user when the end of the breathing air is approaching is termed a) Air depletion alarm b) Low-air indicator c) Breathing air monitor d) Air supply notifier.
Scuba divers, similar to SCBA users, must be aware of their remaining breathable air to ensure their safety underwater. They rely on gauges attached to their tanks, which show the current gas levels and pressure. A diver must have a basic understanding of gas behavior to calculate the remaining dive time and prevent the risk of gas running out, which could lead to serious health implications. Additionally, as a diver ascends to the surface, ambient pressure decreases, making dissolved gases less soluble and potentially leading to decompression sickness (DCS) if ascent is too rapid. Preventative measures include a controlled ascent rate or decompression stops, and if unsuccessful, treatment using hyperbaric oxygen therapy in decompression chambers may be required.