The placard system for identification of hazards of materials for emergency response follows NFPA standard:

• A. 1001
• B. 1021
• C. 1760
• D. 704

Answer: (D)

NFPA 704 is the standard that defines the placard system used to identify hazards of materials for emergency response. The familiar diamond shows four colored sections: blue for health, red for flammability, yellow for reactivity, and white for special hazards. Each colored area uses a number from 0 to 4 to indicate the severity of the hazard, with higher numbers signaling greater danger. The white section can carry letters or symbols to flag specific hazards, such as water reactivity or oxidizers. This compact system lets responders quickly gauge risk and decide on appropriate PPE, ventilation, and actions at the scene. The other NFPA numbers mentioned relate to firefighter qualifications or emergency management topics, not the hazard identification placards. So the placard system is NFPA 704.