Which is a potential hazard when working in a confined space?

A lack of natural ventilation is a significant hazard when working in a confined space, as it can lead to the accumulation of hazardous gases, vapors, or fumes. In confined areas, the exchange of air is limited, which can result in insufficient oxygen levels and the potential for exposure to toxic substances. This lack of airflow can create an environment where workers are at risk of asphyxiation or poisoning, making it critical to ensure proper ventilation during operations in such spaces.

The other options do not pose the same level of risk as inadequate ventilation. Overly bright lighting might create discomfort or temporarily hinder visibility, but it is not inherently dangerous. Excessive space does not contribute to risks typical of confined spaces, and the presence of fresh air is beneficial, not hazardous, ensuring a safe atmosphere for workers. Therefore, recognizing the implications of inadequate ventilation in confined spaces is crucial for safety and compliance in occupational health practices.