Which placard color indicates a flammable material?

The color red is used for placards indicating flammable materials because it represents fire and the associated hazards. In hazardous materials transportation, the color red is universally recognized as a warning for substances that can ignite easily and pose a risk of fire. This standardization helps ensure that emergency responders and individuals handling these materials can quickly recognize the potential dangers associated with flammable substances, allowing for appropriate safety measures to be implemented.

Each of the other colors is designated for different types of hazards; for example, orange might be associated with explosives, yellow with reactive materials, and white could indicate a non-hazardous or miscellaneous substance. Red's connection to fire makes it the most suitable choice for indicating flammable materials, reinforcing the importance of immediate recognition for safety in hazardous material situations.