UN 1825 — Sodium monoxide
Placard: Corrosive. ERG Guide 157. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1825 is Sodium monoxide, a Class 8 corrosive water-reactive solid assigned to ERG Guide 157. Moisture can convert it to hot caustic sodium hydroxide, creating severe burn and runoff hazards.
Hazard overview: UN 1825 presents caustic dust, violent water-reaction, heat generation and alkaline-runoff hazards. Keep the product dry and use dry compatible control agents under incident command.
Response guidance: For a UN 1825 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 157. Establish incident command, isolate the area, stay upwind, prevent incompatible contact, control runoff and choose entry or fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1825 should emphasize caustic burns, heat from dilution or moisture reaction, dust/mist control, PPE selection and alkaline runoff containment. Use ERG 157, SDS and local SOP.
Regulatory context: Sodium monoxide is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by concentration, formulation, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Sodium monoxide should be stored in tightly closed compatible containers in a cool, dry, well-ventilated area away from water, moisture, bases, oxidizers/reducing agents where incompatible, heat and unauthorized access. Protect containers from corrosion, leakage and contamination.
UN 1825 Quick Details
Common Hazards of UN 1825
- CORROSIVE water-reactive solid; dust or contact may cause severe skin, eye and respiratory injury.
- Reacts violently with water or moist air, generating heat and caustic sodium hydroxide solution.
- Reaction may cause spattering, steam and corrosive mist.
- Non-flammable, but heat and corrosive reaction products can worsen surrounding fire conditions.
- Runoff may become strongly alkaline and corrosive.
- Containers may rupture or fail when heated or contaminated with water.
- Avoid dust generation and moisture contact.
Chemical Identity & Physical Properties
White to gray-white hygroscopic powder or crystalline solid. Odorless. Reacts vigorously with moisture in air.
| Also known as | Disodium oxideSodium oxideCalcined sodaDisodium monoxide |
| CAS Number | 1313-59-3 |
| Appearance | White to gray-white hygroscopic powder or crystalline solid. Odorless. Reacts vigorously with moisture in air. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | 1950C (3542F) sublimes |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water generating heat and forming caustic sodium hydroxide solution. Do not use water directly on material. |
Fireground Response Guidance — UN 1825
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for dust, vapor, mist, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing selected from SDS for corrosive contact.
Isolation & Evacuation
First Actions for a UN 1825 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.
- Avoid breathing vapors, fumes, dust, mist or spray and avoid skin or eye contact.
- Keep water and moisture away from released product unless incident command confirms a compatible cooling or control use.
- Do not touch or walk through spilled 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 leak area and expand the perimeter if vapor, dust, fire involvement, water reaction or unknown concentration is present.
- Use ERG Guide 157, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1825 — Sodium monoxideUse 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.