☣️ UN 3298 • CLASS 2
Ethylene oxide and pentafluoroethane mixture, with not more than 7.9% ethylene oxide
Placard: Non-Flammable Gas. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ 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.
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Quick details
UN 3298
Class: 2
Placard type: Non-Flammable Gas
ERG: Guide 126 (check current ERG)
Isolation: ERG 126: Initial isolation 100m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation for 800m in all directions
Chemical & Response Details
| Also known as | Ethylene oxide/pentafluoroethane blendEtO/HFC-125 mixtureOxirane/R-125 mixtureSterilant gas blend |
| Appearance | Colorless, liquefied compressed gas mixture with a sweet, ether-like odor. Stored under pressure in cylinders as a liquid, vaporizes at room temperature when released. |
| Flash Point | Not applicable (compressed gas mixture) |
| Boiling Point | Approximately -48C (-54F) for pentafluoroethane component |
| Vapor Density | 3.0-3.5 (heavier than air) |
| Water Reactivity | No significant reaction with water, though ethylene oxide component is water-soluble |
| Extinguishing | Dry chemical, CO2, water spray for cooling cylinders; not typically flammable due to low ethylene oxide content |
| PPE | ⚠️ Level B minimum with SCBA required; chemical-resistant gloves and suit; ethylene oxide is a carcinogen and reproductive hazard even at low concentrations |
| Isolation | ERG 126: Initial isolation 100m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation for 800m in all directions |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Some may burn but none ignite readily.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
- Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
- Fire may produce irritating, corrosive and/or toxic gases.
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
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- Consider initial downwind evacuation for at least 500 meters (1/3 mile).
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UN 3298 — Ethylene oxide and pentafluoroethane mix HAZMAT RADIO NOTE — UN 3298
Product: Ethylene oxide and pentafluoroethane mixture, with not more than 7.9% ethylene oxide
Class 2 / Non-Flammable Gas / ERG 126
PPE: Level B minimum with SCBA required; chemical-resistant gloves and suit; ethylene oxide is a carcinogen and reproductive hazard even at low concentrations
ISOLATION: ERG 126: Initial isolation 100m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation for 800m in all directions
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 3298 — Ethylene oxide and pentafluoroethane mixture, with not more than 7.9% ethylene oxide
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 126
Appearance: Colorless, liquefied compressed gas mixture with a sweet, ether-like odor. Stored under pressure in cylinders as a liquid, vaporizes at room temperature when released.
Water Reactivity: No significant reaction with water, though ethylene oxide component is water-soluble
Extinguishing: Dry chemical, CO2, water spray for cooling cylinders; not typically flammable due to low ethylene oxide content
PPE: Level B minimum with SCBA required; chemical-resistant gloves and suit; ethylene oxide is a carcinogen and reproductive hazard even at low concentrations
Isolation: ERG 126: Initial isolation 100m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation for 800m in all directions
— Key Hazards —
• Some may burn but none ignite readily.
• Containers may explode when heated.
• Ruptured cylinders may rocket.
— 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/3298 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3298 Ethylene oxide and pentafluoroethane mixture, with not more than 7.9% ethylene oxide Cls2 ERG126 | allfirefighter.com/hazmat/un/3298SMS / 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/3298
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FAQ
Some may burn but none ignite readily. Containers may explode when heated. Ruptured cylinders may rocket. Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas. Vapors from liquefied gas are initially heavier than air and spread along ground. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating, corrosive and/or toxic gases.
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 B minimum with SCBA required; chemical-resistant gloves and suit; ethylene oxide is a carcinogen and reproductive hazard even at low concentrations
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 126 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.