Which of the following is an example of an atmosphere-supplying respirator?

An atmosphere-supplying respirator is designed to provide clean air from an external source to the user, which is crucial in environments where the air is contaminated or lacks sufficient oxygen. The self-contained breathing apparatus (SCBA) is a prime example because it has its own air supply, allowing the wearer to operate in hazardous atmospheres without relying on the surrounding air. This makes SCBAs vital for firefighters, rescue workers, and others who need to work in toxic or oxygen-deficient environments.

In contrast, the other options do not fit the definition of atmosphere-supplying respirators. Powered air-purifying respirators (PAPRs) rely on a battery-powered fan to draw ambient air through filters; they do not provide separated air supply. Gas masks with canisters only filter out contaminants in the surrounding air but do not supply air from a different source. Non-powered particulate respirators filter out particles from the air but also depend on the surrounding atmosphere for air supply, rather than providing an independent air source. Thus, the SCBA stands out as the correct choice because it meets the criteria of supplying breathable air from a contained source.