UN 1073 — Oxygen, refrigerated liquid (cryogenic liquid)
Placard: Non-Flammable Gas. ERG Guide 122. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1073 is Oxygen, refrigerated liquid (cryogenic liquid), a Class 2 oxidizing gas assigned to ERG Guide 122. It is not flammable itself, but it greatly supports combustion and can make ordinary materials burn violently.
Hazard overview: UN 1073 presents an oxygen-enrichment and pressure-container hazard. Oxygen can accelerate fires, cause oils or organic materials to ignite more easily, and create severe cryogenic frostbite risk when handled as refrigerated liquid.
Response guidance: For a UN 1073 incident, responders should confirm the product using shipping papers, cylinder markings, SDS and ERG Guide 122. Establish incident command, isolate the area, keep combustibles and oils away, cool exposed containers from a protected position and control oxygen-enrichment hazards.
Firefighter training notes: Training for UN 1073 should emphasize compressed/liquefied gas pressure hazards, low-area vapor accumulation, frostbite, cylinder heating and toxic decomposition products during fire. Common errors include entering confined spaces without SCBA, ignoring oxygen monitoring and standing too close to heated cylinders.
Regulatory context: Oxygen, refrigerated liquid (cryogenic liquid) is regulated as a hazardous material for transportation and emergency response purposes. Cylinder, workplace exposure, storage, reporting and environmental requirements may vary by product, quantity and jurisdiction. Responders should verify current requirements through shipping papers, SDS, cylinder markings, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Oxygen, refrigerated liquid (cryogenic liquid) cylinders or devices should be stored secured in a cool, dry and well-ventilated area, away from heat, physical damage and incompatible materials. Storage areas should prevent cylinder impact, valve damage, unauthorized access and gas accumulation in low or confined spaces.
UN 1073 Quick Details
Common Hazards of UN 1073
- Substance does not burn but will support combustion.
- May strongly accelerate burning and ignite or re-ignite combustibles.
- Oil, grease, fuels, clothing, wood, paper and other combustibles may ignite more easily in an enriched atmosphere.
- Some mixtures or contaminants may react violently with oxygen or oxidizing gas.
- Containers may rupture or rocket when heated.
- Liquefied or cryogenic contact may cause severe frostbite or cold burns.
- Oxygen-enriched atmospheres can make normal materials burn rapidly and intensely.
Chemical Identity & Physical Properties
Clear, pale blue cryogenic liquid with no odor. Boils at -183°C (-297°F) and produces colorless oxygen gas vapor.
| Also known as | LOXLiquid oxygenCryogenic oxygenLO2Oxygen cryogenic liquid |
| CAS Number | 7782-44-7 |
| Appearance | Clear, pale blue cryogenic liquid with no odor. Boils at -183°C (-297°F) and produces colorless oxygen gas vapor. |
| Flash Point | Not applicable (non-flammable oxidizer) |
| Boiling Point | -183C (-297F) |
| Vapor Density | 1.1 (heavier than air) |
| Water Reactivity | No significant reaction with water, but intense cold can cause violent boiling/splashing |
Fireground Response Guidance — UN 1073
Extinguishing Media
PPE Requirements
Use SCBA for fire, confined-space or unknown-atmosphere operations. Wear clean protective clothing free of oil/grease contamination, and use insulated gloves and face protection where cryogenic liquid contact is possible.
Isolation & Evacuation
First Actions for a UN 1073 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.
- Do not touch damaged cylinders, tanks, valves or released material unless properly trained and equipped.
- Keep oil, grease, fuels, organic materials and other combustibles away from the release area.
- Eliminate ignition sources and remove combustibles if it is safe to do so.
- Ventilate closed spaces before entering, but only if properly trained, equipped and authorized by incident command.
- Isolate the spill or leak area for at least 100 meters (330 feet) in all directions.
- Cool exposed cylinders or tanks from a protected position if fire or heat exposure is present.
- Use ERG Guide 122, shipping papers, SDS and incident command to set protective actions.
📋 Copy & Share Field Card
UN 1073 — Oxygen, refrigerated liquid (cryogenic lUse 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.