UN 1431 — Sodium methylate, dry
Placard: Spontaneously Combustible. ERG Guide 138. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1431 is Sodium methylate, dry, a water-reactive metal or metal alloy assigned to ERG Guide 138. It can react violently with moisture to release hydrogen and heat, and some alkali metals may ignite or explode on contact.
Hazard overview: UN 1431 presents hydrogen generation, violent water reaction and metal fire hazards. Water, foam or CO2 may worsen the incident; use shipping papers, SDS and incident command to confirm compatible dry agents.
Response guidance: For a UN 1431 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 138. Establish incident command, isolate the area, stay upwind, keep water and foam away from the material unless command confirms compatibility, monitor for reaction gases where possible and use only compatible dry agents.
Firefighter training notes: Training for UN 1431 should emphasize dangerous-when-wet behavior, flammable hydrogen gas generation, dry-agent selection, moisture exclusion and safe standoff. Common errors include using water or foam directly, entering low areas without monitoring and underestimating re-ignition. Use ERG 138, SDS and hazmat SOP.
Regulatory context: Sodium methylate, dry 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 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 methylate, dry should be stored in tightly closed compatible containers in a cool, dry, well-ventilated area away from water, moisture, acids, oxidizers, heat and ignition sources. Protect containers from impact, corrosion, air exposure where relevant and unauthorized access.
UN 1431 Quick Details
Common Hazards of UN 1431
- DANGEROUS WHEN WET; contact with water or moisture can release flammable hydrogen gas.
- May ignite on contact with water or moist air.
- Reaction with water may generate heat, pressure and violent spattering.
- May be ignited by heat, sparks or flames and may re-ignite after apparent extinguishment.
- Containers may rupture or explode when heated.
- Runoff or water application may spread contamination and increase gas generation.
- Avoid low, enclosed or poorly ventilated areas where reaction gases may accumulate.
Chemical Identity & Physical Properties
White to off-white powder or crystalline solid. Odorless or slight alcohol-like odor. Hygroscopic and moisture sensitive.
| Also known as | Sodium methoxideMethyl alcohol sodium saltSodium methanolateMethanolic sodium |
| CAS Number | 124-41-4 |
| Appearance | White to off-white powder or crystalline solid. Odorless or slight alcohol-like odor. Hygroscopic and moisture sensitive. |
| Flash Point | Not applicable (reacts with moisture before ignition point reached) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water producing flammable methanol vapor and heat; may ignite spontaneously |
Fireground Response Guidance — UN 1431
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for any suspected flammable hydrogen gas, fire, vapor or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS and incident command; keep PPE and tools dry when working near the material.
Isolation & Evacuation
First Actions for a UN 1431 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 low areas where flammable hydrogen gas may collect.
- Do not touch spilled material or damaged containers unless properly trained and equipped.
- Keep water, foam and moisture away from the released material unless incident command confirms a compatible cooling or control use.
- 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 water contact, fire or gas generation is suspected.
- Use ERG Guide 138, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1431 — Sodium methylate, dryUse 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.