In an environment containing 15% oxygen, what type of respirator is required?

• A. A standard air-purifying respirator
• B. A simple cloth mask
• C. One that pumps oxygen into the mask
• D. A filter with only organic vapor cartridges

Answer: (C)

In an environment with only 15% oxygen, the air is oxygen-deficient, so a respirator must supply breathing gas rather than rely on ambient air. A respirator that pumps oxygen into the mask provides its own source of oxygen, making it the safe choice in this situation. Standard air-purifying respirators rely on ambient oxygen and cannot guarantee enough O2 delivery when the surrounding air is so low. A simple cloth mask offers little protection, and a filter with only organic vapor cartridges does not supply oxygen or protect against general inhalation hazards in an oxygen-deficient space.