What constitutes a "hazardous atmosphere" in a confined space?

A "hazardous atmosphere" in a confined space is defined primarily by conditions that are either lacking in sufficient oxygen or are contaminated with toxic substances. Low oxygen levels can pose serious risks since oxygen is essential for life; an atmosphere with insufficient oxygen can lead to asphyxiation or unconsciousness. Furthermore, the presence of toxic gases poses a direct threat to the health and safety of individuals working in or entering a confined space.

On the other hand, an atmosphere described as having good ventilation or clean air and normal pressure would not be classified as hazardous. High humidity levels may create discomfort or contribute to other environmental stresses, but they do not inherently indicate hazardous atmospheric conditions in terms of toxicity or oxygen deficiency. Thus, the correct understanding focuses on the critical importance of oxygen levels and toxic gas presence when assessing atmospheric hazards in confined spaces.