Which of the following materials is a known fire hazard and requires special storage?

Oily rags and wipes are considered a known fire hazard due to their ability to spontaneously combust when they are not properly handled or stored. These materials can retain heat after being used, especially if they are soaked with flammable substances like oils or solvents. When they are stacked or bundled, the heat can build up, leading to ignition without an external flame source.

Special storage measures, such as using metal containers with self-closing lids specifically designed for flammable materials, are crucial in workplaces to reduce the risk of fire. This handling practice is essential for maintaining safety in an environment where flammable materials are present and helps in compliant waste management procedures.

In contrast, while cardboard, plastic containers, and wooden pallets can all be flammable under certain conditions, they do not present the same level of risk associated with oily rags, which require more stringent safety protocols to prevent fire hazards.