Oxygen

Oxygen (O₂) is essential for human life, with normal atmospheric concentration at 20.9%. When concentrations fall below 19.5%, the atmosphere is considered oxygen deficient, and when levels rise above 23.5%, it becomes oxygen enriched—both conditions pose serious safety hazards. Oxygen depletion often results from displacement by gases such as carbon dioxide, nitrogen, propane, methane, or helium, and can occur in confined spaces, inert gas–blanketed areas, or locations where oxygen is consumed through oxidation or respiration. Excess oxygen is just as dangerous. In an enriched atmosphere, fire and explosion risks increase dramatically, and materials that are normally non combustible can ignite with surprising intensity. Enrichment may occur due to leaking oxygen cylinders, malfunctions in medical oxygen systems, or industrial processes that use high purity oxygen. A properly installed O₂ depletion detector or confined space oxygen sensor provides continuous monitoring and early warning, helping protect personnel from both oxygen deficiency and oxygen enrichment.