☣️ UN 1841 • CLASS 9
UN 1841 — Acetaldehyde ammonia
Placard: Miscellaneous. ERG Guide 171. 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 1841 Quick Details
UN 1841
Product name: Acetaldehyde ammonia
DOT Class: 9
Placard type: Miscellaneous
ERG Guide: 171 (check current ERG)
Initial isolation: ERG 171: isolate spill 25m all directions; if large spill isolate 50m; no evacuation distance specified unless fire involved
Common Hazards of UN 1841
- Some may burn but none ignite readily.
- Containers may explode when heated.
- Some may be transported hot.
- For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported
- Polymeric beads, expandable (UN2211) may evolve flammable vapours.
- Inhalation of material may be harmful.
- Contact may cause burns to skin and eyes.
- Inhalation of Asbestos dust may have a damaging effect on the lungs.
Chemical Identity & Physical Properties
| Also known as | 1-AminoethanolAldehyde ammoniaAcetaldehyde-ammonia |
| CAS Number | 75-39-8 |
| Appearance | White to yellowish crystalline solid or powder with a faint ammonia-like odor at room temperature. |
| Flash Point | Not applicable (solid) |
| Boiling Point | Decomposes before boiling |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water; no violent reaction under normal conditions |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1841
Extinguishing Media
Dry chemical, CO2, water spray acceptable for fire control
PPE Requirements
⚠️ Level C minimum; chemical-resistant gloves and eye protection; SCBA if heated or decomposing
Isolation & Evacuation
ERG 171: isolate spill 25m all directions; if large spill isolate 50m; no evacuation distance specified unless fire involved
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 171).
First Actions for a UN 1841 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.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- 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 1841 — Acetaldehyde ammoniaHAZMAT RADIO NOTE — UN 1841
Product: Acetaldehyde ammonia
Class 9 / Miscellaneous / ERG 171
PPE: Level C minimum; chemical-resistant gloves and eye protection; SCBA if heated or decomposing
ISOLATION: ERG 171: isolate spill 25m all directions; if large spill isolate 50m; no evacuation distance specified unless fire involved
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 1841 — Acetaldehyde ammonia
Class: 9 | Placard: Miscellaneous | ERG Guide: 171
Appearance: White to yellowish crystalline solid or powder with a faint ammonia-like odor at room temperature.
Water Reactivity: Soluble in water; no violent reaction under normal conditions
Extinguishing: Dry chemical, CO2, water spray acceptable for fire control
PPE: Level C minimum; chemical-resistant gloves and eye protection; SCBA if heated or decomposing
Isolation: ERG 171: isolate spill 25m all directions; if large spill isolate 50m; no evacuation distance specified unless fire involved
— Key Hazards —
• Some may burn but none ignite readily.
• Containers may explode when heated.
• Some may be transported hot.
— 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.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/1841 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1841 Acetaldehyde ammonia Cls9 ERG171 | ERG 171: isolate spill 25m all directions; if large spill isolate 50m; no evacua | allfirefighter.com/hazmat/un/1841SMS / 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/1841
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Frequently Asked Questions about UN 1841
Some may burn but none ignite readily. Containers may explode when heated. Some may be transported hot. For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported Polymeric beads, expandable (UN2211) may evolve flammable vapours. Inhalation of material may be harmful. Contact may cause burns to skin and eyes. Inhalation of Asbestos dust may have a damaging effect on the lungs.
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 C minimum; chemical-resistant gloves and eye protection; SCBA if heated or decomposing
Water reactivity: Soluble in water; no violent reaction under normal conditions. Recommended extinguishing: Dry chemical, CO2, water spray acceptable for fire control.
ERG Guide 171 recommendation: ERG 171: isolate spill 25m all directions; if large spill isolate 50m; no evacuation distance specified unless fire involved
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 171 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.