☣️ DOT HAZMAT CLASS 2

Gases

Compressed, liquefied, or dissolved gases—pressure, BLEVE potential, toxic/asphyxiation risk.

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⚠️ Training/quick-reference only. For real incidents, follow your SOP/SOG and the current ERG.
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Common hazards (high level)
  • Pressure release / projectile hazards
  • BLEVE potential when heated
  • Toxic inhalation or asphyxiation
How to recognize
  • Cylinders, tanks, or bulk gas transport
  • Frosting, hissing, vapor clouds
  • Placards indicating Class 2.x
First actions (before Hazmat team)
  • Stage upwind and control ignition sources
  • Isolate; evacuate threatened areas
  • Cool exposed containers from safe positions (if directed)
  • Request Hazmat; monitor atmosphere as per SOP
  • Consult current ERG for protective actions
What NOT to do
  • Do not enter vapor clouds without appropriate PPE
  • Do not approach heated tanks without standoff
  • Do not assume vapor is visible
Common examples
PropaneChlorineAmmoniaCO2 cylindersLPG
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

A Boiling Liquid Expanding Vapor Explosion can occur when a pressurized vessel fails under heat, releasing energy and fragments.

Many gas releases follow wind direction; upwind staging reduces inhalation risk.

Isolation, evacuation, ignition control, and Hazmat request—then ERG/SOP guided actions.
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.