☣️ UN 3298 • CLASS 2
UN 3298 — Ethylene oxide and pentafluoroethane mixture, with not more than 7.9% ethylene oxide
Placard: Non-Flammable Gas. ERG Guide 126. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ 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.
Ethylene oxide and pentafluoroethane mixture, with not more than 7.9% ethylene oxide is a compressed sterilant gas mixture containing ethylene oxide at limited concentration. It is still treated as toxic and potentially carcinogenic during leaks.
Hazard overview: Ethylene oxide mixtures may not ignite readily in this classification, but heated cylinders can rupture. Released gas can displace air and expose responders to toxic EtO vapors.
Response guidance: Isolate the cylinder or leak area, stay upwind, ventilate cautiously and protect containers from heat. Use SCBA and chemical protective clothing for leak control or rescue near the release.
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UN 3298 Quick Details
UN 3298
Product name: Ethylene oxide and pentafluoroethane mixture, with not more than 7.9% ethylene oxide
DOT Class: 2
Placard type: Non-Flammable Gas
ERG Guide: 126 (check current ERG)
Initial 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
Common Hazards of UN 3298
- 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.
Chemical Identity & Physical Properties
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.
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3298
Extinguishing Media
Dry chemical, CO2, water spray for cooling cylinders; not typically flammable due to low ethylene oxide content
PPE Requirements
⚠️ Level B minimum with SCBA required; chemical-resistant gloves and suit; ethylene oxide is a carcinogen and reproductive hazard even at low concentrations
Level B minimum with SCBA required; chemical-resistant gloves and suit; ethylene oxide is a carcinogen and reproductive hazard even at low concentrations.
Isolation & Evacuation
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
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 126).
First Actions for a UN 3298 Incident
- CALL 911, then contact the emergency response telephone number shown on shipping papers, if available.
- 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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📋 Copy & Share Field Card
UN 3298 — Ethylene oxide and pentafluoroethane mixHAZMAT 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 contact the emergency response telephone number shown on shipping papers, if available.
• 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/ethylene-oxide-and-pentafluoroethane-un-3298 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3298 Ethylene oxide and pentafluoroethane mixture, with not more than 7.9% ethylene oxide Cls2 ERG126 | allfirefighter.com/hazmat/un/ethylene-oxide-and-pentafluoroethane-un-3298SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/ethylene-oxide-and-pentafluoroethane-un-3298
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Frequently Asked Questions about UN 3298
UN 3298 is Ethylene oxide and pentafluoroethane mixture, with not more than 7.9% ethylene oxide, assigned to ERG Guide 126 and placarded as Non-Flammable Gas.
Yes. Ethylene oxide HFC-125 mixture presents a serious toxic exposure hazard; avoid inhalation, ingestion, skin contact and contaminated runoff.
Yes, corrosive effects are possible. Avoid skin and eye contact and use chemical-resistant protection.
Gas can spread downwind, collect in low or confined areas, displace oxygen or create toxic exposure depending on the material.
Use caution. No significant reaction with water, though ethylene oxide component is water-soluble
Dry chemical, CO2, water spray for cooling cylinders; not typically flammable due to low ethylene oxide content.
Level B minimum with SCBA required; chemical-resistant gloves and suit; ethylene oxide is a carcinogen and reproductive hazard even at low concentrations.
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.