☣️ UN 2474 • CLASS 6
UN 2474 — Thiophosgene
Placard: Toxic. ERG Guide 156. 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 2474 Quick Details
UN 2474
Product name: Thiophosgene
DOT Class: 6
Placard type: Toxic
ERG Guide: 156 (check current ERG)
Initial isolation: ERG 156: isolate spill/leak area immediately for at least 100m in all directions; if fire or large spill, isolate 800m and consider evacuation 1600m downwind
Common Hazards of UN 2474
- Combustible material: may burn but does not ignite readily.
- Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
- When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
- Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas
- Vapors may travel to source of ignition and flash back.
- Corrosives in contact with metals may evolve flammable hydrogen gas.
- Containers may explode when heated or if contaminated with water.
- TOXIC and/or CORROSIVE; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
Chemical Identity & Physical Properties
| Also known as | Thiocarbonyl chlorideCarbonothioic dichlorideCSCl2Thiophosgene gas |
| CAS Number | 463-71-8 |
| Appearance | Reddish-brown to yellow liquid with a suffocating, pungent odor. Volatile liquid at room temperature, readily vaporizes. |
| Flash Point | Not applicable (reacts with moisture, decomposes before conventional flash point) |
| Boiling Point | 73C (163F) |
| Vapor Density | 4.0 (much heavier than air) |
| Water Reactivity | Reacts with water and moisture releasing HCl, H2S, and other toxic/corrosive gases; avoid water contact |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2474
Extinguishing Media
Dry chemical, CO2, or dry sand only; do not use water or foam
PPE Requirements
⚠️ Level A required; fully encapsulating chemical protective suit with SCBA; extreme toxicity hazard
Isolation & Evacuation
ERG 156: isolate spill/leak area immediately for at least 100m in all directions; if fire or large spill, isolate 800m and consider evacuation 1600m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 156).
First Actions for a UN 2474 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
- 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 2474 — ThiophosgeneHAZMAT RADIO NOTE — UN 2474
Product: Thiophosgene
Class 6 / Toxic / ERG 156
PPE: Level A required; fully encapsulating chemical protective suit with SCBA; extreme toxicity hazard
ISOLATION: ERG 156: isolate spill/leak area immediately for at least 100m in all directions; if fire or large spill, 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 2474 — Thiophosgene
Class: 6 | Placard: Toxic | ERG Guide: 156
Appearance: Reddish-brown to yellow liquid with a suffocating, pungent odor. Volatile liquid at room temperature, readily vaporizes.
Water Reactivity: Reacts with water and moisture releasing HCl, H2S, and other toxic/corrosive gases; avoid water contact
Extinguishing: Dry chemical, CO2, or dry sand only; do not use water or foam
PPE: Level A required; fully encapsulating chemical protective suit with SCBA; extreme toxicity hazard
Isolation: ERG 156: isolate spill/leak area immediately for at least 100m in all directions; if fire or large spill, isolate 800m and consider evacuation 1600m downwind
— Key Hazards —
• Combustible material: may burn but does not ignite readily.
• Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
• When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
— 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/2474 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2474 Thiophosgene Cls6 ERG156 | ERG 156: isolate spill/leak area immediately for at least 100m in all directions | allfirefighter.com/hazmat/un/2474SMS / 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/2474
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Frequently Asked Questions about UN 2474
Combustible material: may burn but does not ignite readily. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas Vapors may travel to source of ignition and flash back. Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water. TOXIC and/or CORROSIVE; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
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 toxicity hazard
Water reactivity: Reacts with water and moisture releasing HCl, H2S, and other toxic/corrosive gases; avoid water contact. Recommended extinguishing: Dry chemical, CO2, or dry sand only; do not use water or foam.
ERG Guide 156 recommendation: ERG 156: isolate spill/leak area immediately for at least 100m in all directions; if fire or large spill, isolate 800m and consider evacuation 1600m downwind
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 156 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.