What does the white section of the NFPA 704 "diamond" signify?

The white section of the NFPA 704 "diamond" signifies special hazards. This section is used to identify specific hazards that are not covered by the other three categories—flammability, health, and reactivity. Special hazards can include things like radiation, acid, oxygen, or corrosive materials. The use of symbols or letters, such as the "radiation" symbol, within the white section provides additional visual indicators to alert responders to these unique risks. Understanding the significance of the white section is crucial for proper risk assessment and ensuring the safety of personnel when dealing with hazardous materials.