USCG Third Assistant Engineer 2025 – 400 Free Practice Questions for Engineering Safety & Environmental Protection Exam

The appropriate percentage of oxygen to maintain in a tank loaded with fuel is critical for ensuring safe operations. The correct answer is that a tank should contain approximately 8 percent oxygen when loaded with fuel.

This level of oxygen concentration is crucial because it allows for adequate combustion of the fuel while minimizing the risk of creating a potentially explosive atmosphere. Too low of an oxygen level can lead to inefficient combustion, while too high a concentration increases the chance of an explosive reaction if flammable vapors are present.

Maintaining an 8 percent oxygen level strikes a balance that supports proper operational safety measures, aligns with safety regulations, and mitigates risks associated with fuel loading. Therefore, understanding the importance of the oxygen percentage in creating a safe environment during fuel operations is essential for any marine engineer or personnel involved in such processes.