UN 2190 — Oxygen difluoride, compressed
Placard: Toxic Gas. ERG Guide 124. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2190 is Oxygen difluoride, compressed, a toxic strong oxidizing gas assigned to ERG Guide 124. It can vigorously support combustion and react with many materials.
Hazard overview: TOXIC and STRONG OXIDIZING compressed gas; inhalation may be fatal. Does not burn but can vigorously support combustion and ignite many materials. May react violently with fuels, organics, reducing agents and many common materials.
Response guidance: For a UN 2190 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 124. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff or vapor spread and base entry/fire-control actions on monitoring and local SOP.
Firefighter training notes: Training for UN 2190 should emphasize toxic gas isolation, air monitoring, downwind protection, Level A entry decisions, cylinder control, decontamination and medical coordination. Use ERG 124, SDS and local SOP.
Regulatory context: Oxygen difluoride, compressed is regulated as a hazardous material for transportation and emergency response purposes. Storage, workplace exposure, emergency planning, spill reporting, waste handling and environmental requirements vary by exact product, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, container markings and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Oxygen difluoride, compressed containers should be secured in a cool, ventilated gas storage area away from heat, physical damage and incompatible materials. Toxic, corrosive, oxidizing or refrigerated gases require leak detection/ventilation and emergency planning as specified by SDS and local code.
UN 2190 Quick Details
Common Hazards of UN 2190
- TOXIC and STRONG OXIDIZING compressed gas; inhalation may be fatal.
- Does not burn but can vigorously support combustion and ignite many materials.
- May react violently with fuels, organics, reducing agents and many common materials.
- Gas or liquefied gas contact may cause severe chemical injury and/or frostbite.
- Containers may rupture or rocket when heated.
- Fire may produce toxic fluorine/fluoride-containing gases.
- Exact tactics require specialist oxidizer/toxic gas procedures and remote isolation.
Chemical Identity & Physical Properties
Colorless gas or pale yellow liquid when compressed. Pungent, foul odor. Extremely corrosive and toxic oxidizing gas.
| 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 |
Fireground Response Guidance — UN 2190
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and fully encapsulating chemical protective clothing for close entry or unknown concentrations. Level A may be needed; protect against frostbite where liquefied or refrigerated gas contact is possible.
Isolation & Evacuation
First Actions for a UN 2190 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Treat the release as a serious inhalation hazard and consider downwind protective actions using ERG and incident command.
- Avoid breathing vapors, gas, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers or spilled/released material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or release area and expand the perimeter for fire involvement, vapor spread, gas accumulation, cylinder heating or unknown product identity.
- Use ERG Guide 124, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2190 — Oxygen difluoride, compressedUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.