What common feature is found on all hazmat container placards?

The common feature found on all hazmat container placards is a color code. Hazmat placards use specific colors to represent different types of hazardous materials, making it easier for first responders and others to quickly identify the nature of the danger associated with the materials being transported. Each color corresponds to a different classification of hazard, helping to communicate critical safety information at a glance.

While bar codes, warning symbols, and registration numbers can also play roles in the identification and handling of hazardous materials, they are not universally present on all hazmat placards. The use of color coding is standardized to ensure consistency and recognition across various types of hazardous materials and containers, which is essential for safety and compliance during transportation.