☣️ UN 1749 • CLASS 2
UN 1749 — Chlorine trifluoride
Placard: Toxic Gas. ERG Guide 124. 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 1749 Quick Details
UN 1749
Product name: Chlorine trifluoride
DOT Class: 2
Placard type: Toxic Gas
ERG Guide: 124 (check current ERG)
Initial isolation: ERG 124: Initial isolation 200m all directions. Protective action distance: 0.8km (day) or 2.4km (night) for large spills.
Common Hazards of UN 1749
- TOXIC and/or CORROSIVE; may be fatal if inhaled or absorbed through skin.
- Fire will produce irritating, corrosive and/or toxic gases.
- Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
- Runoff from fire control or dilution water may cause environmental contamination.
- Substance does not burn but will support combustion.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- These are strong oxidizers and will react vigorously or explosively with many materials including fuels.
- May ignite combustibles (wood, paper, oil, clothing, etc.).
Chemical Identity & Physical Properties
| Also known as | ClF3Chlorine fluorideTrifluorochlorineChlorotrifluoride |
| CAS Number | 7790-91-2 |
| Appearance | Colorless to pale greenish-yellow gas or liquid with a pungent, irritating odor. Highly reactive and corrosive. Liquefied under pressure. |
| Flash Point | Not applicable (oxidizer, does not burn but supports combustion) |
| Boiling Point | 11.8°C (53.2°F) |
| Vapor Density | 3.14 (heavier than air) |
| Water Reactivity | Reacts violently with water, producing toxic and corrosive gases (HF, HCl). Do not use water for extinguishment. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1749
Extinguishing Media
Do not use water, foam, or CO2. Use dry sand, dry chemical powder, or soda ash for small fires. Withdraw from large fires.
PPE Requirements
⚠️ Level A required - fully encapsulating chemical protective suit with SCBA. Extreme corrosive hazard to skin and respiratory system.
Isolation & Evacuation
ERG 124: Initial isolation 200m all directions. Protective action distance: 0.8km (day) or 2.4km (night) for large spills.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 124).
First Actions for a UN 1749 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.
- See Table 1 - Initial Isolation and Protective Action Distances.
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📋 Copy & Share Field Card
UN 1749 — Chlorine trifluorideHAZMAT RADIO NOTE — UN 1749
Product: Chlorine trifluoride
Class 2 / Toxic Gas / ERG 124
PPE: Level A required - fully encapsulating chemical protective suit with SCBA. Extreme corrosive hazard to skin and respiratory system.
ISOLATION: ERG 124: Initial isolation 200m all directions. Protective action distance: 0.8km (day) or 2.4km (night) for large spills.
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 1749 — Chlorine trifluoride
Class: 2 | Placard: Toxic Gas | ERG Guide: 124
Appearance: Colorless to pale greenish-yellow gas or liquid with a pungent, irritating odor. Highly reactive and corrosive. Liquefied under pressure.
Water Reactivity: Reacts violently with water, producing toxic and corrosive gases (HF, HCl). Do not use water for extinguishment.
Extinguishing: Do not use water, foam, or CO2. Use dry sand, dry chemical powder, or soda ash for small fires. Withdraw from large fires.
PPE: Level A required - fully encapsulating chemical protective suit with SCBA. Extreme corrosive hazard to skin and respiratory system.
Isolation: ERG 124: Initial isolation 200m all directions. Protective action distance: 0.8km (day) or 2.4km (night) for large spills.
— Key Hazards —
• TOXIC and/or CORROSIVE; may be fatal if inhaled or absorbed through skin.
• Fire will produce irritating, corrosive and/or toxic gases.
• 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/1749 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1749 Chlorine trifluoride Cls2 ERG124 | ERG 124: Initial isolation 200m all directions. Protective action distance: 0.8k | allfirefighter.com/hazmat/un/1749SMS / 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/1749
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Frequently Asked Questions about UN 1749
TOXIC and/or CORROSIVE; may be fatal if inhaled or absorbed through skin. Fire will produce irritating, corrosive and/or toxic gases. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Runoff from fire control or dilution water may cause environmental contamination. Substance does not burn but will support combustion. Vapors from liquefied gas are initially heavier than air and spread along ground. These are strong oxidizers and will react vigorously or explosively with many materials including fuels. May ignite combustibles (wood, paper, oil, clothing, etc.).
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 A required - fully encapsulating chemical protective suit with SCBA. Extreme corrosive hazard to skin and respiratory system.
Water reactivity: Reacts violently with water, producing toxic and corrosive gases (HF, HCl). Do not use water for extinguishment.. Recommended extinguishing: Do not use water, foam, or CO2. Use dry sand, dry chemical powder, or soda ash for small fires. Withdraw from large fires..
ERG Guide 124 recommendation: ERG 124: Initial isolation 200m all directions. Protective action distance: 0.8km (day) or 2.4km (night) for large spills.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 124 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.