☣️ UN 1942 • CLASS 5
UN 1942 — Ammonium nitrate, with not more than 0.2% combustible substances
Placard: Oxidizer. ERG Guide 140. 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 1942 Quick Details
UN 1942
Product name: Ammonium nitrate, with not more than 0.2% combustible substances
DOT Class: 5
Placard type: Oxidizer
ERG Guide: 140 (check current ERG)
Initial isolation: ERG 140: isolate spill/leak 50m all directions. Large fire: isolate 800m all directions, consider evacuation 800m downwind.
Common Hazards of UN 1942
- These substances will accelerate burning when involved in a fire.
- Some may decompose explosively when heated or involved in a fire.
- May explode from heat or contamination.
- Some will react explosively with hydrocarbons (fuels).
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
- Inhalation, ingestion or contact (skin, eyes) with vapors or substance may cause severe injury, burns or
Chemical Identity & Physical Properties
| Also known as | Nitric acid ammonium saltNorway saltpeterAmmonium saltpeterAN fertilizer |
| CAS Number | 6484-52-2 |
| Appearance | White to gray crystalline solid or pellets. Odorless. Hygroscopic (absorbs moisture from air). |
| Flash Point | Not applicable (oxidizer, non-combustible) |
| Boiling Point | Decomposes at 210C (410F) before boiling |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Dissolves readily in water, no violent reaction. Solutions may be acidic. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1942
Extinguishing Media
Water spray, dry chemical. Keep cool with water spray from a distance.
PPE Requirements
⚠️ Level B minimum; SCBA required in fire conditions. Protective gloves and eye protection for handling.
Isolation & Evacuation
ERG 140: isolate spill/leak 50m all directions. Large fire: isolate 800m all directions, consider evacuation 800m downwind.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 140).
First Actions for a UN 1942 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 100 meters (330 feet).
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UN 1942 — Ammonium nitrate, with not more than 0.2HAZMAT RADIO NOTE — UN 1942
Product: Ammonium nitrate, with not more than 0.2% combustible substances
Class 5 / Oxidizer / ERG 140
PPE: Level B minimum; SCBA required in fire conditions. Protective gloves and eye protection for handling.
ISOLATION: ERG 140: isolate spill/leak 50m all directions. Large fire: isolate 800m all directions, consider evacuation 800m 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 1942 — Ammonium nitrate, with not more than 0.2% combustible substances
Class: 5 | Placard: Oxidizer | ERG Guide: 140
Appearance: White to gray crystalline solid or pellets. Odorless. Hygroscopic (absorbs moisture from air).
Water Reactivity: Dissolves readily in water, no violent reaction. Solutions may be acidic.
Extinguishing: Water spray, dry chemical. Keep cool with water spray from a distance.
PPE: Level B minimum; SCBA required in fire conditions. Protective gloves and eye protection for handling.
Isolation: ERG 140: isolate spill/leak 50m all directions. Large fire: isolate 800m all directions, consider evacuation 800m downwind.
— Key Hazards —
• These substances will accelerate burning when involved in a fire.
• Some may decompose explosively when heated or involved in a fire.
• May explode from heat or contamination.
— 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/1942 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1942 Ammonium nitrate, with not more than 0.2% combustible substances Cls5 ERG140 | allfirefighter.com/hazmat/un/1942SMS / 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/1942
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Frequently Asked Questions about UN 1942
These substances will accelerate burning when involved in a fire. Some may decompose explosively when heated or involved in a fire. May explode from heat or contamination. Some will react explosively with hydrocarbons (fuels). May ignite combustibles (wood, paper, oil, clothing, etc.). Containers may explode when heated. Runoff may create fire or explosion hazard. Inhalation, ingestion or contact (skin, eyes) with vapors or substance may cause severe injury, burns 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 in fire conditions. Protective gloves and eye protection for handling.
Water reactivity: Dissolves readily in water, no violent reaction. Solutions may be acidic.. Recommended extinguishing: Water spray, dry chemical. Keep cool with water spray from a distance..
ERG Guide 140 recommendation: ERG 140: isolate spill/leak 50m all directions. Large fire: isolate 800m all directions, consider evacuation 800m downwind.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 140 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.