Which of the following is NOT a potential cause of fire in a marine sanitation system?

Improper material use would not typically contribute to a fire risk in a marine sanitation system. While the materials selected for a sanitation system should be compatible with marine environments to prevent corrosion, leaks, or blockages, they are not directly associated with ignition sources or combustion. Marine sanitation systems are designed to safely handle waste and are often constructed from materials that are not flammable.

In contrast, other factors like leaks and blockages can create conditions conducive to fire hazards. A leak could potentially lead to exposure of flammable substances or create a risky environment if waste comes into contact with ignition sources. Similarly, a blockage in the waste flow could create pressure buildup, which might lead to ruptures or other failures that risk involving flammable elements. Improperly designed ventilation can trap gases that are not only unpleasant but may also be flammable, creating hazardous conditions.

Thus, the material choice during the design and assembly of a marine sanitation system, while crucial for functionality and durability, is less likely to contribute to fire hazard risks compared to the other factors listed.