☣️ UN 1357 • CLASS 4
UN 1357 — Urea nitrate, wetted with not less than 20% water
Placard: Flammable Solid. ERG Guide 113. 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 1357 Quick Details
UN 1357
Product name: Urea nitrate, wetted with not less than 20% water
DOT Class: 4
Placard type: Flammable Solid
ERG Guide: 113 (check current ERG)
Initial isolation: ERG 113: isolate spill/leak area immediately for 25-50m in all directions; if fire or dried material suspected, isolate 800m radius and evacuate 1600m downwind
Common Hazards of UN 1357
- Flammable/combustible material.
- May be ignited by heat, sparks or flames.
- DRIED OUT material may explode if exposed to heat, flame, friction or shock; treat as an
- Keep material wet with water or treat as an explosive (GUIDE 112).
- Runoff to sewer may create fire or explosion hazard.
- Some are toxic and may be fatal if inhaled, ingested or absorbed through skin. Specifically,
- Contact may cause burns to skin and eyes.
- Fire may produce irritating, corrosive and/or toxic gases.
Chemical Identity & Physical Properties
| Also known as | Urea mononitrateCarbamide nitrateNitrate of ureaAcidum uricum nitricum |
| CAS Number | 124-47-0 |
| Appearance | White to pale yellow crystalline solid or powder. Odorless or slight ammonia-like odor when wet. Shipped as a wetted paste or slurry with at least 20% water for safety. |
| Flash Point | Not applicable (oxidizing solid, not itself flammable but sustains combustion) |
| Boiling Point | Not applicable (decomposes before boiling at approximately 152-159C/306-318F) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water; no violent reaction. Water acts as desensitizer to prevent detonation. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1357
Extinguishing Media
Water spray, fog, or foam acceptable when wet; dry chemical or sand for small fires if dried material suspected
PPE Requirements
⚠️ Level B minimum; full protective clothing, face shield, and SCBA required. Treat dried material as shock-sensitive explosive requiring Level A and bomb squad notification.
Isolation & Evacuation
ERG 113: isolate spill/leak area immediately for 25-50m in all directions; if fire or dried material suspected, isolate 800m radius and evacuate 1600m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 113).
First Actions for a UN 1357 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 immediately for at least 100 meters (330 feet) in all directions.
- Consider initial evacuation for 500 meters (1/3 mile) in all directions.
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📋 Copy & Share Field Card
UN 1357 — Urea nitrate, wetted with not less thanHAZMAT RADIO NOTE — UN 1357
Product: Urea nitrate, wetted with not less than 20% water
Class 4 / Flammable Solid / ERG 113
PPE: Level B minimum; full protective clothing, face shield, and SCBA required. Treat dried material as shock-sensitive explosive requiring Level A and bomb squad notification.
ISOLATION: ERG 113: isolate spill/leak area immediately for 25-50m in all directions; if fire or dried material suspected, isolate 800m radius and evacuate 1600m downwind
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 1357 — Urea nitrate, wetted with not less than 20% water
Class: 4 | Placard: Flammable Solid | ERG Guide: 113
Appearance: White to pale yellow crystalline solid or powder. Odorless or slight ammonia-like odor when wet. Shipped as a wetted paste or slurry with at least 20% water for safety.
Water Reactivity: Soluble in water; no violent reaction. Water acts as desensitizer to prevent detonation.
Extinguishing: Water spray, fog, or foam acceptable when wet; dry chemical or sand for small fires if dried material suspected
PPE: Level B minimum; full protective clothing, face shield, and SCBA required. Treat dried material as shock-sensitive explosive requiring Level A and bomb squad notification.
Isolation: ERG 113: isolate spill/leak area immediately for 25-50m in all directions; if fire or dried material suspected, isolate 800m radius and evacuate 1600m downwind
— Key Hazards —
• Flammable/combustible material.
• May be ignited by heat, sparks or flames.
• DRIED OUT material may explode if exposed to heat, flame, friction or shock; treat as an
— 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/1357 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1357 Urea nitrate, wetted with not less than 20% water Cls4 ERG113 | allfirefighter.com/hazmat/un/1357SMS / 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/1357
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Frequently Asked Questions about UN 1357
Flammable/combustible material. May be ignited by heat, sparks or flames. DRIED OUT material may explode if exposed to heat, flame, friction or shock; treat as an Keep material wet with water or treat as an explosive (GUIDE 112). Runoff to sewer may create fire or explosion hazard. Some are toxic and may be fatal if inhaled, ingested or absorbed through skin. Specifically, Contact may cause burns to skin and eyes. Fire may produce irritating, corrosive and/or toxic gases.
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; full protective clothing, face shield, and SCBA required. Treat dried material as shock-sensitive explosive requiring Level A and bomb squad notification.
Water reactivity: Soluble in water; no violent reaction. Water acts as desensitizer to prevent detonation.. Recommended extinguishing: Water spray, fog, or foam acceptable when wet; dry chemical or sand for small fires if dried material suspected.
ERG Guide 113 recommendation: ERG 113: isolate spill/leak area immediately for 25-50m in all directions; if fire or dried material suspected, isolate 800m radius and evacuate 1600m downwind
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 113 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.