UN 1437 — Zirconium hydride
Placard: Flammable Solid. ERG Guide 138. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1437 is Zirconium hydride, a dangerous-when-wet hydride or borohydride assigned to ERG Guide 138. Water or moist air can release hydrogen gas and heat, sometimes violently.
Hazard overview: UN 1437 presents hydride water-reaction, hydrogen generation and ignition hazards. Keep the material dry, avoid incompatible cleanup and use only compatible dry agents under incident command.
Response guidance: For a UN 1437 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 138. Establish incident command, isolate the area, stay upwind, prevent incompatible contact and choose extinguishing or spill-control actions based on the ERG, SDS and local SOP.
Firefighter training notes: Training for UN 1437 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: Zirconium hydride 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: Zirconium hydride 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, dust release where relevant and unauthorized access.
UN 1437 Quick Details
Common Hazards of UN 1437
- 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.
- Hydride dust or residue may ignite after moisture exposure or incompatible cleanup.
Chemical Identity & Physical Properties
Gray to black metallic powder or crystalline solid, odorless. Stable in dry air but reacts with moisture.
| Also known as | Zirconium dihydrideZirconium hydride powderZirconium(II) hydrideZrH2 |
| CAS Number | 7704-99-6 |
| Appearance | Gray to black metallic powder or crystalline solid, odorless. Stable in dry air but reacts with moisture. |
| Flash Point | Not applicable (pyrophoric solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts with water producing flammable hydrogen gas and heat; may ignite spontaneously in moist air |
Fireground Response Guidance — UN 1437
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for any suspected flammable hydrogen gas, fire, dust 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 near the material.
Isolation & Evacuation
First Actions for a UN 1437 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 1437 — Zirconium hydrideUse 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.