Which part of the NFPA label indicates reactivity hazards?

The part of the NFPA (National Fire Protection Association) label that indicates reactivity hazards is represented by the yellow section. This color signifies the potential chemical reactivity of a substance, helping first responders quickly assess how a material may react under certain conditions, such as exposure to heat or other chemicals. By using the yellow quadrant to denote reactivity, the NFPA label provides essential information that is crucial for safe handling and emergency response planning.

In addition to representing reactivity, the other colors on the NFPA label serve different purposes: red indicates flammability hazards, blue signifies health hazards, and white is used for specific hazards or additional information. Each color plays a vital role in providing a quick, visual summary of the hazards associated with a substance.