Final answer:
Foaming plastics should not be used as the floor liner for Division 1.1 or 1.2 hazardous materials because they can create static electricity and lack structural integrity for safe containment.
Step-by-step explanation:
The material that should not be used as the floor liner for Division 1.1 or 1.2 hazardous materials is foaming plastics. These materials can fall under the United States Department of Transportation hazardous materials regulations. Division 1.1 materials are substances with a mass explosion hazard, while Division 1.2 materials are substances with a projection hazard but not a mass explosion hazard. For safe transportation and storage, it is critical to use appropriate materials that do not react dangerously with the cargo. Foaming plastics are known to have the potential to create static electricity or may not have enough structural integrity to safely contain a hazardous material spill, making them an unsuitable choice for liner materials in these cases.