Which piece of information is NOT necessary to determine if you need to use placards?

To determine the necessity of using placards, the focus is primarily on the characteristics of the hazardous materials being transported and the regulations that govern their transportation. The manufacturing date of the material is not relevant for placarding requirements. Specific information that is crucial includes the type of hazardous material, as it informs the necessary handling and transportation procedures, and the hazard class, which categorizes the material based on the risk it poses. Additionally, the quantity being transported is important, as it influences the need for placarding based on regulatory criteria. Therefore, the manufacturing date does not impact whether or not placards are required, making it the correct choice.