NEBOSH Practice Test

What is considered a dangerous characteristic of a confined space?

1. Limited Oxygen Supply

2. Excessive Brightness

3. High Temperature

4. Open Ventilation

The correct answer is: Limited Oxygen Supply

A limited oxygen supply is considered a dangerous characteristic of a confined space because it poses a significant risk to the health and safety of individuals entering or working within that space. In confined spaces, oxygen levels can become depleted for various reasons, such as chemical reactions, the presence of rust or other oxidizing agents, or the displacement of air by other gases. When the oxygen concentration falls below the safe threshold (typically below 19.5% for most industrial applications), it can lead to symptoms of hypoxia, loss of consciousness, and ultimately death if not addressed promptly. Moreover, confined spaces often have restricted airflow, making it difficult for fresh air to circulate and replenish oxygen levels. This creates a high-risk environment for anyone entering the space without proper monitoring and safety protocols in place. Therefore, recognizing and addressing the risks associated with limited oxygen supply is crucial for preventing dangerous incidents in the workplace. In contrast, excessive brightness and high temperature, while they may present challenges, do not inherently carry the same life-threatening risk as a lack of oxygen. Open ventilation is typically associated with reducing hazards in confined spaces by allowing for the exchange of air, thereby potentially eliminating both low oxygen levels and the buildup of hazardous gases.