☣️ DOT Hazmat Classification
Gases
Compressed, liquefied, or dissolved gases—pressure, BLEVE potential, toxic/asphyxiation risk.
🟥
DOT CLASS 2
Advertisement
Common Hazards — Class 2
- Pressure release / projectile hazards
- BLEVE potential when heated
- Toxic inhalation or asphyxiation
How to Recognize Class 2
- Cylinders, tanks, or bulk gas transport
- Frosting, hissing, vapor clouds
- Placards indicating Class 2.x
First Actions Before Hazmat Team Arrives
Initial priorities for DOT Hazmat Class 2 (Gases) incidents. These are general guidelines — always verify with shipping papers, consult the current ERG, and follow your SOP/SOG.
- 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 — Class 2
- Do not enter vapor clouds without appropriate PPE
- Do not approach heated tanks without standoff
- Do not assume vapor is visible
Common Examples — Class 2 Gases
PropaneChlorineAmmoniaCO2 cylindersLPG
These are representative examples only. Product-specific hazards vary — always confirm via shipping papers and current ERG.
Common UN Numbers in Class 2 (Gases)
UN 1001Acetylene, dissolvedUN 1002Air, compressedUN 1003Air, refrigerated liquid (cryogenic liquid)UN 1005Ammonia, anhydrousUN 1006Argon, compressedUN 1008Boron trifluoride, compressedUN 1009Refrigerant gas R-13B1UN 1011ButaneUN 1012ButyleneUN 1013Carbon dioxide, compressedUN 1016Carbon monoxide, compressedUN 1017ChlorineUN 1018ChlorodifluoromethaneUN 1020ChloropentafluoroethaneUN 10211-Chloro-1,2,2,2- tetrafluoroethane
More UN numbers discoverable via the Hazmat Hub. Always consult current ERG + SOP/SOG for operations.
Advertisement
FAQ — DOT Hazmat Class 2 (Gases)
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: DOT/PHMSA hazard class concepts, NFPA 704 overview, and ERG usage principles. This guide does not reproduce ERG guide text — always consult the current ERG for incident-specific protective actions.