What is a significant hazard associated with confined spaces?

Atmospheric hazards are a primary concern in confined spaces because these environments can have dangerous conditions that may not be readily apparent. For example, low oxygen levels can lead to asphyxiation, while the presence of toxic gases can result in serious illness or even death. These hazards are particularly insidious because they often go unnoticed until a worker experiences symptoms, which can happen quickly in an enclosed space.

In confined spaces, the balance of gases in the atmosphere can be disrupted for various reasons, such as ongoing chemical reactions, decay of organic matter, or the introduction of harmful materials. Proper monitoring and ventilation are critical to ensuring the safety of personnel entering and working in these environments, which is why understanding and recognizing atmospheric hazards is essential for safe confined space operations.

Other options, while they may pose risks in specific situations, do not represent the significant, immediate dangers that can arise from the unique characteristics of confined spaces.