☣️ UN 1437 • CLASS 4
Zirconium hydride
Placard: Flammable Solid. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
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Quick details
UN 1437
Class: 4
Placard type: Flammable Solid
ERG: Guide 138 (check current ERG)
Isolation: ERG 138: isolate 100m all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation
Chemical & Response Details
| 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 |
| Extinguishing | Dry chemical, sand, dry graphite powder; DO NOT use water, foam, or CO2 |
| PPE | ⚠️ Level B minimum; SCBA required; chemical-resistant gloves and clothing; avoid moisture exposure |
| Isolation | ERG 138: isolate 100m all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Produce flammable gases on contact with water.
- May ignite on contact with water or moist air.
- Some react vigorously or explosively on contact with water.
- May be ignited by heat, sparks or flames.
- May re-ignite after fire is extinguished.
- Some are transported in highly flammable liquids.
- Runoff may create fire or explosion hazard.
- Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- Consider initial downwind evacuation for at least 300 meters (1000 feet).
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UN 1437 — Zirconium hydride HAZMAT RADIO NOTE — UN 1437
Product: Zirconium hydride
Class 4 / Flammable Solid / ERG 138
PPE: Level B minimum; SCBA required; chemical-resistant gloves and clothing; avoid moisture exposure
ISOLATION: ERG 138: isolate 100m all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 1437 — Zirconium hydride
Class: 4 | Placard: Flammable Solid | ERG Guide: 138
Appearance: Gray to black metallic powder or crystalline solid, odorless. Stable in dry air but reacts with moisture.
Water Reactivity: Reacts with water producing flammable hydrogen gas and heat; may ignite spontaneously in moist air
Extinguishing: Dry chemical, sand, dry graphite powder; DO NOT use water, foam, or CO2
PPE: Level B minimum; SCBA required; chemical-resistant gloves and clothing; avoid moisture exposure
Isolation: ERG 138: isolate 100m all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation
— Key Hazards —
• Produce flammable gases on contact with water.
• May ignite on contact with water or moist air.
• Some react vigorously or explosively on contact with water.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/1437 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1437 Zirconium hydride Cls4 ERG138 | ERG 138: isolate 100m all directions; if tank/rail car involved in fire, isolate | allfirefighter.com/hazmat/un/1437SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/1437
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FAQ
Produce flammable gases on contact with water. May ignite on contact with water or moist air. Some react vigorously or explosively on contact with water. May be ignited by heat, sparks or flames. May re-ignite after fire is extinguished. Some are transported in highly flammable liquids. Runoff may create fire or explosion hazard. Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level B minimum; SCBA required; chemical-resistant gloves and clothing; avoid moisture exposure
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 138 and your department SOP/SOG for incident-specific protective actions.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles. This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.