☣️ UN 3138 • CLASS 2
Ethylene, acetylene and propylene mixture, refrigerated liquid containing at least 71.5% ethylene with not more than 22.5% acetylene and not more than 6% propylene
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 3138
Class: 2
Placard type: Flammable Gas
ERG: Guide 115 (check current ERG)
Isolation: ERG 115: isolate 800m all directions initially; evacuate 1600m downwind if tank fire; extreme explosion hazard in confined spaces
Chemical & Response Details
| Also known as | Refrigerated ethylene-acetylene-propylene mixtureCryogenic hydrocarbon gas mixtureLiquefied C2-C3 olefin blendEthylene-rich refrigerated gas mixture |
| Appearance | Colorless cryogenic liquid with a faint sweet odor. Boils at extremely low temperature, producing flammable vapors. Refrigerated to maintain liquid state during transport. |
| Flash Point | Not applicable (cryogenic flammable gas mixture, auto-ignites well below normal temperatures) |
| Boiling Point | Approximately -104°C (-155°F) for ethylene component; mixture boils at cryogenic temperatures |
| Vapor Density | 0.98 (slightly lighter than air at normal temperature, but cold vapors are heavier) |
| Water Reactivity | No significant reaction with water, but rapid vaporization creates extreme fire/explosion hazard |
| Extinguishing | Dry chemical, CO2, water spray for cooling only; foam ineffective on cryogenic gas fires |
| PPE | ⚠️ Level A with SCBA required; cryogenic gloves and face shield mandatory for liquid exposure; anti-static clothing |
| Isolation | ERG 115: isolate 800m all directions initially; evacuate 1600m downwind if tank fire; extreme explosion hazard in confined spaces |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- EXTREMELY FLAMMABLE.
- Will be easily ignited by heat, sparks or flames.
- Will form explosive mixtures with air.
- 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.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
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).
Advertisement
📋 Copy & Share
UN 3138 — Ethylene, acetylene and propylene mixtur HAZMAT RADIO NOTE — UN 3138
Product: Ethylene, acetylene and propylene mixture, refrigerated liquid containing at least 71.5% ethylene with not more than 22.5% acetylene and not more than 6% propylene
Class 2 / Flammable Gas / ERG 115
PPE: Level A with SCBA required; cryogenic gloves and face shield mandatory for liquid exposure; anti-static clothing
ISOLATION: ERG 115: isolate 800m all directions initially; evacuate 1600m downwind if tank fire; extreme explosion hazard in confined spaces
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 3138 — Ethylene, acetylene and propylene mixture, refrigerated liquid containing at least 71.5% ethylene with not more than 22.5% acetylene and not more than 6% propylene
Class: 2 | Placard: Flammable Gas | ERG Guide: 115
Appearance: Colorless cryogenic liquid with a faint sweet odor. Boils at extremely low temperature, producing flammable vapors. Refrigerated to maintain liquid state during transport.
Water Reactivity: No significant reaction with water, but rapid vaporization creates extreme fire/explosion hazard
Extinguishing: Dry chemical, CO2, water spray for cooling only; foam ineffective on cryogenic gas fires
PPE: Level A with SCBA required; cryogenic gloves and face shield mandatory for liquid exposure; anti-static clothing
Isolation: ERG 115: isolate 800m all directions initially; evacuate 1600m downwind if tank fire; extreme explosion hazard in confined spaces
— Key Hazards —
• EXTREMELY FLAMMABLE.
• Will be easily ignited by heat, sparks or flames.
• Will form explosive mixtures with air.
— First Actions —
• 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
SOURCE: allfirefighter.com/hazmat/un/3138 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3138 Ethylene, acetylene and propylene mixture, refrigerated liquid containing at least 71.5% ethylene with not more than 22.5% acetylene and not more than 6% propylene Cls2 ERG115 | allfirefighter.com/hazmat/un/3138SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/3138
Advertisement
FAQ
EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. 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. Containers may explode when heated. Ruptured cylinders may rocket.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level A with SCBA required; cryogenic gloves and face shield mandatory for liquid exposure; anti-static clothing
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 115 and your department SOP/SOG for incident-specific protective actions.
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.