☣️ UN 1845 • CLASS 9
UN 1845 — Carbon dioxide, solid
Placard: Miscellaneous. ERG Guide 120. 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 1845 Quick Details
UN 1845
Product name: Carbon dioxide, solid
DOT Class: 9
Placard type: Miscellaneous
ERG Guide: 120 (check current ERG)
Initial isolation: ERG 120: No evacuation distances specified; isolate spill area and ensure adequate ventilation; treat as asphyxiant in confined spaces
Common Hazards of UN 1845
- Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite.
- Non-flammable gases.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
Chemical Identity & Physical Properties
| Also known as | Dry iceSolid carbon dioxideCardiceCarbon dioxide snow |
| CAS Number | 124-38-9 |
| Appearance | White or colorless solid (snow-like or block form) that sublimates directly to gas at -78.5°C (-109.3°F). Odorless. Denser than air. |
| Flash Point | Not applicable (non-flammable) |
| Boiling Point | Not applicable (sublimes at -78.5°C/-109.3°F) |
| Vapor Density | 1.5 (heavier than air) |
| Water Reactivity | No significant reaction, but rapidly sublimates producing large volumes of CO2 gas |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1845
Extinguishing Media
Not applicable (non-flammable); ventilation is primary control measure
PPE Requirements
⚠️ Thermal protective gloves and eye protection required to prevent frostbite; SCBA or escape air if confined space due to asphyxiation hazard
Isolation & Evacuation
ERG 120: No evacuation distances specified; isolate spill area and ensure adequate ventilation; treat as asphyxiant in confined spaces
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 120).
First Actions for a UN 1845 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.
- Consider initial downwind evacuation for at least 100 meters (330 feet).
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UN 1845 — Carbon dioxide, solidHAZMAT RADIO NOTE — UN 1845
Product: Carbon dioxide, solid
Class 9 / Miscellaneous / ERG 120
PPE: Thermal protective gloves and eye protection required to prevent frostbite; SCBA or escape air if confined space due to asphyxiation hazard
ISOLATION: ERG 120: No evacuation distances specified; isolate spill area and ensure adequate ventilation; treat as asphyxiant in confined spaces
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 1845 — Carbon dioxide, solid
Class: 9 | Placard: Miscellaneous | ERG Guide: 120
Appearance: White or colorless solid (snow-like or block form) that sublimates directly to gas at -78.5°C (-109.3°F). Odorless. Denser than air.
Water Reactivity: No significant reaction, but rapidly sublimates producing large volumes of CO2 gas
Extinguishing: Not applicable (non-flammable); ventilation is primary control measure
PPE: Thermal protective gloves and eye protection required to prevent frostbite; SCBA or escape air if confined space due to asphyxiation hazard
Isolation: ERG 120: No evacuation distances specified; isolate spill area and ensure adequate ventilation; treat as asphyxiant in confined spaces
— Key Hazards —
• Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
• Vapors from liquefied gas are initially heavier than air and spread along ground.
• Contact with gas, liquefied gas or cryogenic liquids 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/1845 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1845 Carbon dioxide, solid Cls9 ERG120 | ERG 120: No evacuation distances specified; isolate spill area and ensure adequa | allfirefighter.com/hazmat/un/1845SMS / 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/1845
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Frequently Asked Questions about UN 1845
Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas. Vapors from liquefied gas are initially heavier than air and spread along ground. Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite. Non-flammable gases. Containers may explode when heated. Ruptured cylinders may rocket.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Thermal protective gloves and eye protection required to prevent frostbite; SCBA or escape air if confined space due to asphyxiation hazard
Water reactivity: No significant reaction, but rapidly sublimates producing large volumes of CO2 gas. Recommended extinguishing: Not applicable (non-flammable); ventilation is primary control measure.
ERG Guide 120 recommendation: ERG 120: No evacuation distances specified; isolate spill area and ensure adequate ventilation; treat as asphyxiant in confined spaces
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 120 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.