What does "placarding" refer to in hazardous materials operations?

In hazardous materials operations, "placarding" specifically refers to the use of signs or labels to identify hazardous materials during transport or storage. These signs are essential for communicating information about the type of hazard that the materials present, which helps in ensuring safety for emergency responders and the public. Placards provide critical information at a glance, such as the nature of the chemical, the level of risk it poses, and any necessary precautions that should be taken. This visual identification system is vital for effective emergency response and risk management, allowing individuals to quickly assess the dangers associated with a particular material before engaging with it.

The other options, while relevant to safety and training in hazardous materials management, do not define placarding. Sealing containers is more about containment and preventing leaks, emergency evacuation procedures focus on relocating people safely from danger, and training personnel pertains to educating and preparing individuals for hazardous situations rather than the communication of hazards through placards.