☣️ UN 1427 • CLASS 4
UN 1427 — Sodium hydride
Placard: Dangerous When Wet. ERG Guide 138. 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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UN 1427 Quick Details
UN 1427
Product name: Sodium hydride
DOT Class: 4
Placard type: Dangerous When Wet
ERG Guide: 138 (check current ERG)
Initial isolation: ERG 138: Initial isolation 100m in all directions; protective action distance 300m downwind for large spills
Common Hazards of UN 1427
- 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
Chemical Identity & Physical Properties
| Also known as | Sodium monohydrideNaHSodium hydride dispersion |
| CAS Number | 7646-69-7 |
| Appearance | Gray to silvish-gray crystalline solid or dispersion in mineral oil. Odorless when pure. Extremely reactive with moisture. |
| Flash Point | Not applicable (ignites spontaneously with moisture) |
| Boiling Point | Not applicable (decomposes) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water producing flammable hydrogen gas and heat; may ignite spontaneously |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1427
Extinguishing Media
Dry chemical (Class D metal fire extinguisher), dry sand, dry graphite; NO water or foam
PPE Requirements
⚠️ Level B minimum with SCBA; splash-resistant chemical suit; handle only in dry, inert atmosphere
Isolation & Evacuation
ERG 138: Initial isolation 100m in all directions; protective action distance 300m downwind for large spills
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 138).
First Actions for a UN 1427 Incident
- 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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📋 Copy & Share Field Card
UN 1427 — Sodium hydrideHAZMAT RADIO NOTE — UN 1427
Product: Sodium hydride
Class 4 / Dangerous When Wet / ERG 138
PPE: Level B minimum with SCBA; splash-resistant chemical suit; handle only in dry, inert atmosphere
ISOLATION: ERG 138: Initial isolation 100m in all directions; protective action distance 300m downwind for large spills
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 1427 — Sodium hydride
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 138
Appearance: Gray to silvish-gray crystalline solid or dispersion in mineral oil. Odorless when pure. Extremely reactive with moisture.
Water Reactivity: Reacts violently with water producing flammable hydrogen gas and heat; may ignite spontaneously
Extinguishing: Dry chemical (Class D metal fire extinguisher), dry sand, dry graphite; NO water or foam
PPE: Level B minimum with SCBA; splash-resistant chemical suit; handle only in dry, inert atmosphere
Isolation: ERG 138: Initial isolation 100m in all directions; protective action distance 300m downwind for large spills
— 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/1427 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1427 Sodium hydride Cls4 ERG138 | ERG 138: Initial isolation 100m in all directions; protective action distance 30 | allfirefighter.com/hazmat/un/1427SMS / 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/1427
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Frequently Asked Questions about UN 1427
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 with SCBA; splash-resistant chemical suit; handle only in dry, inert atmosphere
Water reactivity: Reacts violently with water producing flammable hydrogen gas and heat; may ignite spontaneously. Recommended extinguishing: Dry chemical (Class D metal fire extinguisher), dry sand, dry graphite; NO water or foam.
ERG Guide 138 recommendation: ERG 138: Initial isolation 100m in all directions; protective action distance 300m downwind for large spills
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.