Which material is typically not recommended for storing fuel containers?

Storing fuel containers requires materials that can safely contain flammable and potentially hazardous substances. Cardboard is typically not recommended for this purpose because it is a combustible material. Cardboard can easily be affected by spills or leaks, which could cause it to absorb fuel, increasing the risk of fire. Additionally, cardboard lacks the structural integrity needed to safely contain fuel containers, which could lead to accidents if those containers are jostled or dropped.

In contrast, metal, glass, and plastic are more suitable materials for storing fuel. Metal containers, such as steel or aluminum, are strong and resistant to corrosion, providing a secure option for holding fuel. Glass can be used for certain types of fuel but is less common due to its fragility; it, however, is non-reactive and impermeable. Plastic is also widely used because many types of fuel can be safely stored in high-density polyethylene containers, which are lightweight and resistant to many chemical interactions.

Overall, cardboard does not meet the safety standards required for handling and storing fuel, making it the least appropriate choice compared to the other materials listed.