In which of the following scenarios is a confined space likely to become a permit-required space?

A confined space is designated as a permit-required space particularly when it contains hazardous atmospheres. This classification is critical because hazardous atmospheres can pose serious risks to workers, including toxic gases, flammable vapors, or insufficient oxygen levels. The presence of these hazards requires that specific safety measures be implemented, including monitoring the atmosphere and providing appropriate personal protective equipment.

In contrast, simply being ventilated does not automatically deem a confined space as permit-required; ventilation can reduce hazards but may not eliminate them. A space that is large enough for a worker to enter safely might still harbor dangers that necessitate closer scrutiny and safety measures. Furthermore, having a single point of entry is a characteristic of confined spaces but does not, by itself, qualify the space as permit-required unless there are additional hazards present. Therefore, the defining factor for a permit-required confined space is the presence of hazardous atmospheres, which necessitates the rigorous safety protocols established by regulations.