UN 1418 — Magnesium alloys powder
Placard: Dangerous When Wet. ERG Guide 138. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1418 is Magnesium alloys powder, a dangerous-when-wet metal powder assigned to ERG Guide 138. Fine powder can produce hydrogen with moisture and may burn intensely if dispersed, heated or ignited.
Hazard overview: UN 1418 presents water-reactive metal powder, hydrogen generation, dust ignition and re-ignition hazards. Avoid dust clouds, keep the material dry and use only compatible Class D or dry media under incident command.
Response guidance: For a UN 1418 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 1418 should emphasize metal powder dust, hydrogen generation, incompatible extinguishing agents, re-ignition and Class D/dry media selection. Common errors include using water or CO2, disturbing powder and underestimating dust-cloud hazards. Use ERG 138, SDS and metal-fire SOP.
Regulatory context: Magnesium alloys powder 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: Magnesium alloys powder should be stored in tightly closed compatible containers in a cool, dry, well-ventilated area away from water, moisture, oxidizers, acids, heat and ignition sources. Prevent dust release, container damage and contact with incompatible extinguishing agents.
UN 1418 Quick Details
Common Hazards of UN 1418
- 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.
- Fine metal powder dust can ignite or form dust-air explosion hazards if dispersed.
Chemical Identity & Physical Properties
Gray to silver-gray metallic powder with no odor. Dry powder at room temperature, may contain various alloying elements such as aluminum, zinc, or manganese.
| Also known as | Magnesium alloy dustMagnesium metal powder alloysMg alloy powder |
| Appearance | Gray to silver-gray metallic powder with no odor. Dry powder at room temperature, may contain various alloying elements such as aluminum, zinc, or manganese. |
| Flash Point | Not applicable (pyrophoric metal powder) |
| Boiling Point | Not applicable (metal alloy) |
| Vapor Density | Not applicable (solid metal powder) |
| Water Reactivity | Reacts with water to produce flammable hydrogen gas and heat; may ignite spontaneously on contact with water or moist air |
Fireground Response Guidance — UN 1418
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for fire, smoke, dust or confined-space exposure. Protective clothing, gloves and eye/face protection should follow SDS and metal-fire SOP; PPE does not remove dust explosion, water reaction or violent metal fire hazards.
Isolation & Evacuation
First Actions for a UN 1418 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 1418 — Magnesium alloys powderUse 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.