Which of the following characterizes a permit-required confined space?

A permit-required confined space is defined by specific criteria established by safety regulations, primarily focusing on the potential hazards that may be present within the space. The defining characteristic that makes it a permit-required space is the presence of a material that may engulf an entrant. This encompasses situations where a person could be submerged or buried under solids or liquids, leading to asphyxiation or drowning, which represents a serious risk in confined spaces.

This classification is crucial for ensuring the safety of individuals who may need to enter such spaces for work or inspection purposes. The requirement for a permit highlights the need for safety procedures, including atmospheric testing and emergency planning, to protect workers from potential dangers.

While benign atmospheric conditions, non-converging walls, and unrestricted access are factors that may describe certain spaces, they do not fulfill the criteria that necessitate a permit for entry. A confined space can still constitute a hazard even if it appears safe under certain conditions, which is why the evaluation of engulfment risk is central to the designation of a space as permit-required.