Which of the following can cause fuel contamination?

Inadequate tank maintenance can lead to fuel contamination due to several factors associated with tanks that are not properly cared for. When tanks are not regularly cleaned and inspected, sediments, water, and microbial growth can accumulate inside. This can introduce particulates and moisture into the fuel, which compromises its quality and can lead to issues such as corrosion, clogged filters, and inhibited engine performance.

Furthermore, if tanks are not sealed properly, contaminants from the environment, such as dirt or water, can enter the fuel supply. Regular maintenance is crucial to ensure that tanks remain clean and free of contaminants, which helps maintain the overall integrity of the fuel system.

The other options, while positively influencing fuel quality, do not contribute to contamination. A clean fuel source and high-quality fuel additives help maintain fuel purity, while regular system inspections are part of preventive maintenance that helps detect issues before they lead to contamination.