For which type of incident is a supplied-air respirator most likely to be used?

A supplied-air respirator (SAR) is most likely used in scenarios where there is a potential for hazardous atmospheres that can compromise respiratory functions. In an industrial incident, this type of respirator is especially suitable due to the possibility of exposure to toxic gases, vapors, and airborne contaminants often present in such environments.

Industrial sites frequently handle chemicals and materials that can produce harmful substances, making the use of a SAR critical to ensure safety. These respirators provide a continuous flow of clean air from a stationary source, allowing personnel to work in environments where the air quality may be compromised or unknown.

In contrast, while interior attacks on structure fires and other incidents such as aviation or trench rescues may present respiratory hazards, they typically involve the use of self-contained breathing apparatuses (SCBA) which are designed for short-duration operations in more immediate and hazardous environments.