UN 1823 — Sodium hydroxide, solid
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1823 is Sodium hydroxide, solid, a Class 8 caustic corrosive material assigned to ERG Guide 154. It can cause severe alkali burns and may generate heat when dissolved or diluted.
Hazard overview: UN 1823 presents caustic burn, dust/mist, heat-on-dilution and alkaline-runoff hazards. Contact with some metals may release flammable hydrogen gas.
Response guidance: For a UN 1823 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 154. 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 1823 should emphasize caustic burns, heat from dilution, dust or mist control, metal/hydrogen incompatibility, PPE selection and alkaline runoff containment. Use ERG 154, SDS and local SOP.
Regulatory context: Sodium hydroxide, solid 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 hydroxide, solid should be stored in compatible corrosion-resistant containers with secondary containment, away from acids, reactive metals where incompatible, ammonium salts where incompatible and unauthorized access. Keep containers closed and protected from moisture, impact or heat.
UN 1823 Quick Details
Common Hazards of UN 1823
- CORROSIVE caustic material; skin, eye or respiratory contact may cause severe burns.
- Dust, mist, spray or solution can damage eyes, skin and respiratory tissue.
- Dissolving or diluting can generate heat and may cause splattering or boiling.
- Generally non-flammable, but may react with some metals to release flammable hydrogen gas.
- Runoff may be strongly alkaline and corrosive.
- Containers may rupture or fail when heated.
- Exact hazard severity depends on concentration, physical form and SDS.
Chemical Identity & Physical Properties
White to slightly yellow solid, typically in flakes, pellets, or granules. Odorless. Hygroscopic and absorbs moisture and carbon dioxide from air.
| Also known as | Caustic sodaLyeSoda lyeSodium hydrateWhite caustic |
| CAS Number | 1310-73-2 |
| Appearance | White to slightly yellow solid, typically in flakes, pellets, or granules. Odorless. Hygroscopic and absorbs moisture and carbon dioxide from air. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | 1388C (2530F) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Dissolves exothermically in water, generating significant heat that may cause boiling or spattering. Solution is highly corrosive. |
Fireground Response Guidance — UN 1823
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, mist, dust, 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 1823 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.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Avoid creating dust or splashes and prevent alkaline/corrosive runoff from entering drains.
- 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 154, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1823 — Sodium hydroxide, solidUse 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.