For a space to be considered a permit-required confined space, it must contain enough serious hazards that at least one person has been injured or killed in the space.

A space is designated as a permit-required confined space primarily based on the presence of hazards that could potentially lead to serious harm, not solely on the historical occurrence of an injury or fatality. The definition outlines several conditions that would classify a space as a permit-required confined space, including the presence of hazardous atmospheres, the potential for engulfment, or configurations that could impede escape.

Factors such as atmospheric hazards, materials that pose a risk of suffocation or drowning, and physical configurations that could hinder rescue efforts are key to this classification. Thus, a space does not need to have a history of incidents to be classified as such. The intent behind the regulation is to proactively manage risks and ensure safety for workers entering these spaces, rather than relying on past events as a measure of danger.