What does the color yellow indicate on the NFPA 704 diamond?

• A. Flammability
• B. Health hazard
• C. Instability/reactivity
• D. Special hazards

Answer: (C)

The color yellow on the NFPA 704 diamond indicates instability or reactivity. This part of the label is crucial for assessing the potential hazards associated with a material, particularly in emergency situations. An elevated yellow number (higher than 0) signifies an increased risk of the substance reacting vigorously under certain conditions, which could include exposure to heat or contact with water.

Understanding the significance of the yellow section helps emergency responders identify potential hazards related to chemical stability and make informed decisions for safe handling, containment, and mitigation efforts during a hazardous materials incident. The NFPA 704 system allows for quick identification of risks, ensuring that firefighters and other emergency personnel can take appropriate actions to protect themselves and the public.