EMS Operations Practice Test 2026 – Complete Exam Prep for Safety and MCI

NFPA 704 uses a diamond-shaped hazard symbol that appears on chemical labels and placards. The diamond is divided into four colored sections: blue for health risk, red for flammability, yellow for reactivity, and white for special hazards. Numbers from 0 to 4 in the colored sections indicate how severe each hazard is, with higher numbers meaning greater danger; the white section may show indicators like OX for oxidizers or a W with a slash through it for water reactivity. This compact, at-a-glance format helps responders quickly gauge overall risk and choose appropriate protective actions. That diamond shape is the symbol associated with NFPA hazard identification.