Oxygen deficiency is defined as an atmosphere containing less than what percentage of oxygen?

Oxygen deficiency is defined as an atmosphere containing less than 19.5% oxygen. This standard is crucial for ensuring the safety of individuals working in confined spaces, as normal atmospheric air contains approximately 21% oxygen. When the oxygen level falls below 19.5%, it poses health risks, as it can lead to symptoms such as impaired coordination, unconsciousness, or even death if exposure continues.

The definition aligns with OSHA regulations, which aim to protect workers by establishing guidelines for safe environments. Monitoring oxygen levels in confined spaces is therefore essential, and a threshold of 19.5% serves as a critical cutoff to trigger necessary safety measures, including ventilation or the use of supplied air.