Which type of respirator is classified as atmosphere-supplying?

The self-contained breathing apparatus (SCBA) is classified as an atmosphere-supplying respirator because it provides a breathable atmosphere to the user from a compressed supply of air stored within the unit itself. This type of respirator is essential for scenarios where the surrounding air is contaminated or lacks sufficient oxygen, as it allows the user to operate in hazardous environments while ensuring a continuous supply of clean, breathable air.

In contrast, other types of respirators, like the chemical cartridge respirator and powered air-purifying respirators, rely on filtering or purifying the existing air rather than supplying a new source of air. Non-powered particulate respirators serve to filter airborne particles but do not provide an independent air supply, making them unsuitable for use in environments with immediate danger to life or health due to airborne contaminants.