An oxygen-enriched atmosphere contains more than what percentage of oxygen?

An oxygen-enriched atmosphere is defined as an environment where the concentration of oxygen exceeds the normal atmospheric level of approximately 21%. The correct answer, which indicates an oxygen-enriched atmosphere, is 23.5%. This level is significant because it is recognized as a point where the increased presence of oxygen can pose safety hazards, such as enhancing the flammability of materials.

When oxygen levels rise above 23.5%, the potential for fire and combustion increases dramatically, leading to a heightened risk of fire incidents in various settings, especially in industrial or construction environments. This concept is critical in safety training and practices, emphasizing the importance of monitoring and controlling oxygen levels to mitigate risks and ensure a safe working environment.

Lower percentages mentioned in other choices don't meet the criteria for an oxygen-enriched atmosphere, as they fall within the normal range of ambient air, which is not associated with the same level of hazard.