Which statement best explains why oxygen monitoring is required before confined space entry?

• A. To prevent asphyxiation
• B. To calibrate meters
• C. To measure pressure
• D. To reduce noise

Answer: (A)

Oxygen monitoring is essential before entering a confined space because the main hazard inside is the atmosphere itself. If oxygen levels are too low, people can quickly become dizzy, lose consciousness, or die from asphyxiation even without other contaminant exposure. An oxygen monitor checks the percentage of oxygen in the air, ensuring it’s within a safe range for breathing and highlighting any oxygen enrichment that could increase fire risk. By confirming safe oxygen levels first, you reduce the immediate danger to entrants. Calibrating meters, measuring pressure, or reducing noise aren’t the primary reasons for this check, as they pertain to instrument setup, different atmospheric parameters, or unrelated concerns.