In which scenario would you need a permit to enter a confined space?

A permit is required to enter a confined space when there is a potential for a hazardous atmosphere. Confined spaces can present various dangers, such as the accumulation of toxic gases, oxygen deficiency, or the presence of flammable materials. This risk necessitates careful assessment and the use of a permit system to ensure that workers are protected. The permit process typically involves evaluating the space for these hazards, ensuring that appropriate safety measures and equipment are in place, and confirming that personnel are trained to work safely in these environments.

While accessibility and ventilation are important factors when assessing confined spaces, they do not inherently indicate the need for a permit. A space can be accessible and well-ventilated yet still pose a significant risk if hazardous atmospheres are present. Similarly, being below ground level could imply a potentially hazardous situation, but it is not the determining factor for needing a permit unless there are specific atmospheric concerns. Thus, the presence of a hazardous atmosphere is the critical condition that mandates permitting.