A placard with a Class Division number 4.2 indicates what type of material?

A placard with a Class Division number 4.2 specifically signifies spontaneous combustible materials. This classification is used to identify substances that can ignite without an external source of ignition, typically due to self-heating properties or in the presence of moisture. Spontaneous combustibles can pose significant risks during transport and storage because they can lead to uncontrolled fires.

Understanding the specific meaning of each placard is crucial for hazmat technicians, as it informs them about the handling procedures, necessary precautions, and emergency response protocols associated with the materials being transported. Class Division 4.2 is vital for ensuring that those who might come into contact with or respond to these materials are adequately prepared to manage the risks involved.