UN 1432 — Sodium phosphide
Placard: Dangerous When Wet. ERG Guide 139. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1432 is Sodium phosphide, a dangerous-when-wet phosphide assigned to ERG Guide 139. Moisture can release highly toxic and flammable phosphine gas, making air monitoring and moisture exclusion critical.
Hazard overview: UN 1432 presents phosphine inhalation, flammable gas and violent water-reaction hazards. Do not rely on odor; keep the material dry, avoid low areas and use only compatible dry agents under incident command.
Response guidance: For a UN 1432 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 139. 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 1432 should emphasize phosphine generation, air monitoring, moisture exclusion, dry-agent selection and downwind toxic gas control. Common errors include using water or foam directly, relying on garlic odor and entering low areas without monitoring. Use ERG 139, SDS and hazmat SOP.
Regulatory context: Sodium phosphide 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 phosphide 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. Storage should prevent phosphine release and protect containers from damage or unauthorized access.
UN 1432 Quick Details
Common Hazards of UN 1432
- DANGEROUS WHEN WET; contact with water or moisture can release toxic and flammable phosphine 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.
- Phosphine can be rapidly dangerous in low, enclosed or poorly ventilated areas.
- Garlic-like odor is not a reliable safety warning for phosphine exposure.
Chemical Identity & Physical Properties
Dark gray to black crystalline solid or powder. May have a slight phosphine odor when exposed to moisture. Solid at room temperature.
| Also known as | Trisodium phosphideSodium phosphide (Na3P)Phosphide de sodiumNatriumphosphid |
| CAS Number | 12058-85-4 |
| Appearance | Dark gray to black crystalline solid or powder. May have a slight phosphine odor when exposed to moisture. Solid at room temperature. |
| Flash Point | Not applicable (water-reactive solid) |
| Boiling Point | Not applicable (decomposes on contact with water) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water producing highly flammable and toxic phosphine gas (PH3). May ignite spontaneously on contact with moisture or humid air. |
Fireground Response Guidance — UN 1432
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for any suspected phosphine, fire, vapor or confined-space exposure. Chemical-resistant clothing, gloves and eye/face protection should be selected from SDS and incident command; phosphine monitoring is important.
Isolation & Evacuation
First Actions for a UN 1432 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 toxic and flammable phosphine 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 139, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1432 — Sodium phosphideUse 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.