☣️ DOT HAZMAT CLASS 3

Flammable Liquids

Ignitable vapors, rapid fire spread, and runoff—control ignition and protect exposures.

🧯☣️
⚠️ Training/quick-reference only. For real incidents, follow your SOP/SOG and the current ERG.
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Common hazards (high level)
  • Vapor ignition and flash fire potential
  • Runoff spread and secondary fires
  • Toxic combustion products
How to recognize
  • Liquid spills with strong odor or sheen
  • Placard 'Flammable Liquid'
  • Vapor accumulation in low areas
First actions (before Hazmat team)
  • Eliminate ignition sources and control access
  • Approach from upwind; establish isolation
  • Protect exposures; consider vapor suppression per SOP
  • Request Hazmat if unknown/large release
  • Consult ERG and coordinate foam/water strategy
What NOT to do
  • Do not walk through unknown liquids
  • Do not create ignition sources (sparks) near vapors
  • Do not assume diesel behaves like gasoline
Common examples
GasolineDiesel (varies)EthanolPaintAcetone
Popular UN numbers in this class
More UN numbers are discoverable via the Hub lookup. Always consult current ERG + SOP/SOG.
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FAQ

Many flammable liquids burn from vapor above the liquid surface; vapors can travel to ignition sources.

It depends on product and tactics. Use SOP/SOG and Hazmat guidance; foam may be indicated for many flammable liquids.

Life safety: isolate, control ignition, protect exposures, request Hazmat early.
Sources (high level): DOT/PHMSA class & marking concepts, NFPA 704 overview concepts, and ERG usage principles. This guide does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.