Which oxygen range is correct for safety operations?

Which oxygen range is correct for safety operations?

• A. 18-21%
• B. 21-25%
• C. 19-23%
• D. 19.2-22%

Answer: (D)

Maintaining a safe oxygen level in work spaces is about balancing breathable air with fire risk. You want oxygen levels close to normal atmospheric air so people don’t become hypoxic, but not so high that the air becomes oxygen-rich enough to accelerate combustion. A safe operating range should tolerate small changes due to ventilation and measurement error while staying well clear of both deficiency and enrichment hazards. This is why the best choice is the one that stays near normal air without tipping into high-oxygen conditions; it provides a practical margin for readings and environmental shifts. The other options either move toward too little oxygen, risking fainting or impairment, or toward too much oxygen, increasing fire and explosion risk.

Maintaining a safe oxygen level in work spaces is about balancing breathable air with fire risk. You want oxygen levels close to normal atmospheric air so people don’t become hypoxic, but not so high that the air becomes oxygen-rich enough to accelerate combustion. A safe operating range should tolerate small changes due to ventilation and measurement error while staying well clear of both deficiency and enrichment hazards. This is why the best choice is the one that stays near normal air without tipping into high-oxygen conditions; it provides a practical margin for readings and environmental shifts. The other options either move toward too little oxygen, risking fainting or impairment, or toward too much oxygen, increasing fire and explosion risk.