HAZMAT Placards for EMS: A Quick Reference
How to read DOT hazard class placards from a safe distance, ERG lookup basics, and the EMS role at HAZMAT scenes.
October 30, 2026 · 7 min read
EMS at a HAZMAT scene has one job before anything else: don't become a patient. Read the placard from upwind, uphill, upstream — and let hazmat-trained crews do decon.
The nine hazard classes
- 1 — Explosives (orange)
- 2 — Gases (red flammable, green non-flammable, white poison)
- 3 — Flammable liquids (red)
- 4 — Flammable solids (red/white stripes)
- 5 — Oxidizers & organic peroxides (yellow)
- 6 — Poisons & infectious (white)
- 7 — Radioactive (yellow/white)
- 8 — Corrosives (white/black)
- 9 — Miscellaneous (white/black stripes)
The 4-digit UN number
The number in the middle of the placard is the UN identifier. Look it up in the Emergency Response Guide (ERG) — the orange section gives isolation and protective distances.
EMS role at the scene
- Stage upwind, uphill, and outside the isolation zone from ERG.
- Do not enter the hot or warm zone without proper PPE and training.
- Treat patients only after gross decon is complete.
- Notify the receiving ED early so they can prep.
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