What does the number at the bottom of a placard indicate?

The number at the bottom of a placard indicates the UN hazard class of the material. This number is part of the United Nations system used to categorize hazardous materials. Each UN hazard class corresponds to a specific type of risk associated with the material, such as flammability, toxicity, or reactivity. This classification helps in identifying and responding to hazards effectively, ensuring that first responders can take appropriate actions based on the nature of the material involved in an incident.

This system of placarding plays a critical role in the safe transport of hazardous materials, as it provides vital information at a glance to emergency responders and other personnel involved in handling these substances. Understanding the UN hazard class through these numbers allows for better risk assessment and management in hazardous situations.