Which of the following DOT placard color codes refers to health hazards?

The correct choice for the color code referring to health hazards is white. In the system of placards used in the transportation of hazardous materials, each color corresponds to a specific type of hazard.

White placards are used to represent health hazards, indicating potential risks to human health. This could include substances that are toxic, carcinogenic, or that may result in serious health issues upon exposure. The use of a white placard ensures that first responders and anyone else involved in the handling or transportation of these materials are alerted to the potential health dangers, allowing for appropriate safety measures to be taken.

Other colors signify different hazards. For example, green refers to non-flammable gases, blue indicates hazards related to health and protection measures that are less severe than those represented by white, while yellow typically warns of reactivity hazards, signaling that the material may be unstable or undergo dangerous reactions under specific conditions. Understanding these color codes is crucial for effective communication regarding hazardous materials and ensuring safety during emergency response situations.