In the NFPA 704 marking system, which color indicates reactivity?

In the NFPA 704 marking system, yellow is the color that indicates reactivity. The system uses a diamond shape with four quadrants, each representing a different type of hazard: health, flammability, instability, and special hazards.

The yellow quadrant specifically denotes the reactivity hazards of a material, which can include its tendency to explode, to react violently with water, or to polymerize uncontrollably. Understanding this color coding is crucial for emergency responders and workers handling hazardous materials as it provides a quick reference to the potential dangers presented by a substance.

In contrast, red signifies flammability, blue represents health hazards, and white indicates special hazards, such as radiation or acid. Each color serves a distinct purpose that contributes to a comprehensive understanding of the material’s risks. This knowledge is essential for ensuring safety in handling, storage, and response situations involving hazardous substances.