☣️ UN 2190 • CLASS 2
UN 2190 — Oxygen difluoride, compressed
Placard: Toxic Gas. ERG Guide 124. 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 2190 Quick Details
UN 2190
Product name: Oxygen difluoride, compressed
DOT Class: 2
Placard type: Toxic Gas
ERG Guide: 124 (check current ERG)
Initial isolation: ERG 124: isolate 800m all directions initially; evacuate 1600m downwind if leak; 3200m if fire or major spill
Common Hazards of UN 2190
- TOXIC and/or CORROSIVE; may be fatal if inhaled or absorbed through skin.
- Fire will produce irritating, corrosive and/or toxic gases.
- Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
- Runoff from fire control or dilution water may cause environmental contamination.
- Substance does not burn but will support combustion.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- These are strong oxidizers and will react vigorously or explosively with many materials including fuels.
- May ignite combustibles (wood, paper, oil, clothing, etc.).
Chemical Identity & Physical Properties
| Also known as | Oxygen difluorideOF2Fluorine monoxideDifluorine monoxideOxygen fluoride |
| CAS Number | 7783-41-7 |
| Appearance | Colorless gas or pale yellow liquid when compressed. Pungent, foul odor. Extremely corrosive and toxic oxidizing gas. |
| Flash Point | Not applicable (oxidizing gas) |
| Boiling Point | -145C (-229F) |
| Vapor Density | 1.9 (heavier than air) |
| Water Reactivity | Reacts violently with water producing oxygen, hydrofluoric acid, and heat; do not use water |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2190
Extinguishing Media
Do not use water or foam; use dry chemical or CO2 from distance only
PPE Requirements
⚠️ Level A required; full encapsulating suit with SCBA; extreme corrosive and toxic hazard
Isolation & Evacuation
ERG 124: isolate 800m all directions initially; evacuate 1600m downwind if leak; 3200m if fire or major spill
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 124).
First Actions for a UN 2190 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.
- See Table 1 - Initial Isolation and Protective Action Distances.
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📋 Copy & Share Field Card
UN 2190 — Oxygen difluoride, compressedHAZMAT RADIO NOTE — UN 2190
Product: Oxygen difluoride, compressed
Class 2 / Toxic Gas / ERG 124
PPE: Level A required; full encapsulating suit with SCBA; extreme corrosive and toxic hazard
ISOLATION: ERG 124: isolate 800m all directions initially; evacuate 1600m downwind if leak; 3200m if fire or major spill
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 2190 — Oxygen difluoride, compressed
Class: 2 | Placard: Toxic Gas | ERG Guide: 124
Appearance: Colorless gas or pale yellow liquid when compressed. Pungent, foul odor. Extremely corrosive and toxic oxidizing gas.
Water Reactivity: Reacts violently with water producing oxygen, hydrofluoric acid, and heat; do not use water
Extinguishing: Do not use water or foam; use dry chemical or CO2 from distance only
PPE: Level A required; full encapsulating suit with SCBA; extreme corrosive and toxic hazard
Isolation: ERG 124: isolate 800m all directions initially; evacuate 1600m downwind if leak; 3200m if fire or major spill
— Key Hazards —
• TOXIC and/or CORROSIVE; may be fatal if inhaled or absorbed through skin.
• Fire will produce irritating, corrosive and/or toxic gases.
• Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
— 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/2190 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2190 Oxygen difluoride, compressed Cls2 ERG124 | allfirefighter.com/hazmat/un/2190SMS / 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/2190
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Frequently Asked Questions about UN 2190
TOXIC and/or CORROSIVE; may be fatal if inhaled or absorbed through skin. Fire will produce irritating, corrosive and/or toxic gases. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Runoff from fire control or dilution water may cause environmental contamination. Substance does not burn but will support combustion. Vapors from liquefied gas are initially heavier than air and spread along ground. These are strong oxidizers and will react vigorously or explosively with many materials including fuels. May ignite combustibles (wood, paper, oil, clothing, etc.).
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 required; full encapsulating suit with SCBA; extreme corrosive and toxic hazard
Water reactivity: Reacts violently with water producing oxygen, hydrofluoric acid, and heat; do not use water. Recommended extinguishing: Do not use water or foam; use dry chemical or CO2 from distance only.
ERG Guide 124 recommendation: ERG 124: isolate 800m all directions initially; evacuate 1600m downwind if leak; 3200m if fire or major spill
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 124 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.