☣️ UN 2073 • CLASS 2
UN 2073 — Ammonia solution, with more than 35% but not more than 50% ammonia
Placard: Non-Flammable Gas. ERG Guide 125. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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 2073 Quick Details
UN 2073
Product name: Ammonia solution, with more than 35% but not more than 50% ammonia
DOT Class: 2
Placard type: Non-Flammable Gas
ERG Guide: 125 (check current ERG)
Initial isolation: ERG 125: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m downwind
Common Hazards of UN 2073
- TOXIC and/or CORROSIVE; may be fatal if inhaled, ingested or absorbed through skin.
- Vapors are extremely irritating and corrosive.
- Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
- Fire will produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may cause environmental contamination.
- Some may burn but none ignite readily.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Some of these materials may react violently with water.
Chemical Identity & Physical Properties
| Also known as | Aqua ammoniaAmmonium hydroxide solutionAmmonia waterHousehold ammonia (concentrated)Aqueous ammonia |
| CAS Number | 1336-21-6 |
| Appearance | Clear to slightly yellow liquid with a pungent, suffocating odor. Strong irritating ammonia smell detectable at very low concentrations. |
| Flash Point | Not applicable (non-flammable solution) |
| Boiling Point | Approximately 24-38C (75-100F) depending on concentration |
| Vapor Density | 0.6 (lighter than air, ammonia vapor rises) |
| Water Reactivity | Miscible with water; dilution generates heat but no violent reaction |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2073
Extinguishing Media
Water spray, fog, or mist preferred for vapor knockdown; avoid direct water streams
PPE Requirements
⚠️ Level B minimum; SCBA and chemical-resistant suit required; butyl rubber gloves; face shield with goggles
Isolation & Evacuation
ERG 125: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 125).
First Actions for a UN 2073 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.
- Many gases are heavier than air and will spread along the ground and collect in low or confined areas
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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📋 Copy & Share Field Card
UN 2073 — Ammonia solution, with more than 35% butHAZMAT RADIO NOTE — UN 2073
Product: Ammonia solution, with more than 35% but not more than 50% ammonia
Class 2 / Non-Flammable Gas / ERG 125
PPE: Level B minimum; SCBA and chemical-resistant suit required; butyl rubber gloves; face shield with goggles
ISOLATION: ERG 125: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 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 2073 — Ammonia solution, with more than 35% but not more than 50% ammonia
Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 125
Appearance: Clear to slightly yellow liquid with a pungent, suffocating odor. Strong irritating ammonia smell detectable at very low concentrations.
Water Reactivity: Miscible with water; dilution generates heat but no violent reaction
Extinguishing: Water spray, fog, or mist preferred for vapor knockdown; avoid direct water streams
PPE: Level B minimum; SCBA and chemical-resistant suit required; butyl rubber gloves; face shield with goggles
Isolation: ERG 125: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m downwind
— Key Hazards —
• TOXIC and/or CORROSIVE; may be fatal if inhaled, ingested or absorbed through skin.
• Vapors are extremely irritating and corrosive.
• Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
— 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.
• Many gases are heavier than air and will spread along the ground and collect in low or confined areas
SOURCE: allfirefighter.com/hazmat/un/2073 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2073 Ammonia solution, with more than 35% but not more than 50% ammonia Cls2 ERG125 | allfirefighter.com/hazmat/un/2073SMS / 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/2073
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Frequently Asked Questions about UN 2073
TOXIC and/or CORROSIVE; may be fatal if inhaled, ingested or absorbed through skin. Vapors are extremely irritating and corrosive. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may cause environmental contamination. Some may burn but none ignite readily. Vapors from liquefied gas are initially heavier than air and spread along ground. Some of these materials may react violently with water.
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 and chemical-resistant suit required; butyl rubber gloves; face shield with goggles
Water reactivity: Miscible with water; dilution generates heat but no violent reaction. Recommended extinguishing: Water spray, fog, or mist preferred for vapor knockdown; avoid direct water streams.
ERG Guide 125 recommendation: ERG 125: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m downwind
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 125 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.