☣️ UN 3340 • CLASS 2
UN 3340 — Refrigerant gas R-407C
Placard: Non-Flammable Gas. ERG Guide 126. 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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UN 3340 Quick Details
UN 3340
Product name: Refrigerant gas R-407C
DOT Class: 2
Placard type: Non-Flammable Gas
ERG Guide: 126 (check current ERG)
Initial isolation: ERG 126: isolate spill/leak area 100m in all directions; if tank/rail car involved in fire, isolate 800m in all directions
Common Hazards of UN 3340
- 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
| Also known as | R-407CHFC-407CDifluoromethane/Pentafluoroethane/Tetrafluoroethane blendR-32/R-125/R-134a mixture |
| CAS Number | 75-68-3 |
| Appearance | Colorless, liquefied gas with slight ethereal odor. Shipped as a pressurized liquid blend of three hydrofluorocarbons. Heavier than air. |
| Flash Point | Not applicable (non-flammable gas) |
| Boiling Point | -43.6C (-46.5F) |
| Vapor Density | 3.0 (heavier than air) |
| Water Reactivity | No significant reaction with water |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3340
Extinguishing Media
Not applicable (non-flammable); water spray may be used for cooling containers
PPE Requirements
⚠️ Level B minimum; SCBA required in high concentrations due to asphyxiation hazard; insulated gloves for liquid contact
Isolation & Evacuation
ERG 126: isolate spill/leak area 100m in all directions; if tank/rail car involved in fire, isolate 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 3340 Incident
- 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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📋 Copy & Share Field Card
UN 3340 — Refrigerant gas R-407CHAZMAT RADIO NOTE — UN 3340
Product: Refrigerant gas R-407C
Class 2 / Non-Flammable Gas / ERG 126
PPE: Level B minimum; SCBA required in high concentrations due to asphyxiation hazard; insulated gloves for liquid contact
ISOLATION: ERG 126: isolate spill/leak area 100m in all directions; if tank/rail car involved in fire, isolate 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 3340 — Refrigerant gas R-407C
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 126
Appearance: Colorless, liquefied gas with slight ethereal odor. Shipped as a pressurized liquid blend of three hydrofluorocarbons. Heavier than air.
Water Reactivity: No significant reaction with water
Extinguishing: Not applicable (non-flammable); water spray may be used for cooling containers
PPE: Level B minimum; SCBA required in high concentrations due to asphyxiation hazard; insulated gloves for liquid contact
Isolation: ERG 126: isolate spill/leak area 100m in all directions; if tank/rail car involved in fire, isolate 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/3340 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3340 Refrigerant gas R-407C Cls2 ERG126 | ERG 126: isolate spill/leak area 100m in all directions; if tank/rail car involv | allfirefighter.com/hazmat/un/3340SMS / 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/3340
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Frequently Asked Questions about UN 3340
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; SCBA required in high concentrations due to asphyxiation hazard; insulated gloves for liquid contact
Water reactivity: No significant reaction with water. Recommended extinguishing: Not applicable (non-flammable); water spray may be used for cooling containers.
ERG Guide 126 recommendation: ERG 126: isolate spill/leak area 100m in all directions; if tank/rail car involved in fire, isolate 800m in all directions
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.