☣️ UN 3374 • CLASS 2.1
Acetylene, solvent free
Placard: Flammable Gas. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
Advertisement
Quick details
UN 3374
Class: 2.1
Placard type: Flammable Gas
ERG: Guide 116 (check current ERG)
Verify shipping papers and exact product details; use ERG Guide 116 for initial actions and isolation/evacuation guidance.
Common hazards (high level)
- EXTREMELY FLAMMABLE.
- Will be easily ignited by heat, sparks or flames.
- Will form explosive mixtures with air. Acetylene (UN1001, UN3374) may react explosively even in the
- Disilane (UN3553) and Silane (UN2203) will ignite spontaneously in air and may re-ignite.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Vapors may travel to source of ignition and flash back.
- Cylinders exposed to fire may vent and release flammable gas through pressure relief devices.
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Many gases are heavier than air and will spread along the ground and collect in low or confined areas
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- Consider initial downwind evacuation for at least 800 meters (1/2 mile).
Related UN numbers (same class)
This is a discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
Copy / share note
MAYDAY / HAZMAT QUICK NOTE UN 3374 — Acetylene, solvent free Class: 2.1 | Placard: Flammable Gas ERG: Guide 116 (check current ERG) FIRST ACTIONS: use SOP/SOG + ERG; stage upwind; isolate; deny entry; request Hazmat.
Advertisement
FAQ
A UN/NA number is a four-digit identifier used in transport markings and placards to help identify hazardous materials for emergency response.
No. This page is a training/quick-reference aid. Always consult the current ERG and follow your SOP/SOG for incident-specific protective actions.
Common locations include placards, orange panels, shipping papers, SDS documents, container markings, rail car/vehicle IDs, and facility signage.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles. This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.