Can air purifying respirators be used in an atmosphere that is oxygen deficient?

Air purifying respirators are not suitable for use in oxygen-deficient atmospheres because they rely on filtering out contaminants from the air. These respirators work by drawing in ambient air, which must have a sufficient level of oxygen for the wearer to breathe safely. If the atmosphere is deficient in oxygen, these devices cannot supply the necessary oxygen levels, which can lead to asphyxiation.

In environments where the oxygen concentration falls below safe levels (typically below 19.5% oxygen), relying on air purifying respirators can pose a significant risk to the user. In such situations, alternative respiratory protection devices, like supplied-air respirators or self-contained breathing apparatus (SCBA), should be used to ensure the safety and health of the worker. This fundamental understanding of the operational limits and suitable contexts for different respiratory protection devices is essential in ensuring safety in hazardous work environments.