What is a common hazard encountered in manholes?

A common hazard encountered in manholes is the lack of ventilation. Manholes can often be confined spaces, which may contain hazardous gases or be oxygen-deficient. If there is inadequate ventilation, workers may be at risk of exposure to toxic substances, as well as suffocation. Thus, ensuring proper ventilation is critical for safety when working in these environments.

While the presence of fall hazards or dangerous traps may be a concern, they are not as universally applicable as the lack of ventilation in manholes. Heavy equipment collisions can occur in areas around manholes but are less specific to the hazards posed inside an actual manhole. Excessive lighting is not a common hazard associated with manholes; in fact, proper lighting is essential for safety and visibility. Therefore, understanding the risks associated with confined spaces, specifically the need for proper ventilation, is vital for worker safety in this context.