☣️ UN 2729 • CLASS 6
UN 2729 — Hexachlorobenzene
Placard: Toxic. ERG Guide 152. 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.
Hexachlorobenzene is a persistent toxic chlorinated solid. Response priorities are exposure control, contamination control and runoff containment.
Hazard overview: Hexachlorobenzene presents a serious toxic exposure hazard and a contamination hazard. Fire can produce dense toxic chlorinated smoke even if the solid is not easily ignited.
Response guidance: Isolate the area, avoid dust generation and prevent runoff from reaching drains or waterways. Use dry chemical, CO2, foam or water spray for the surrounding fire and cool containers from a protected position.
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UN 2729 Quick Details
UN 2729
Product name: Hexachlorobenzene
DOT Class: 6
Placard type: Toxic
ERG Guide: 152 (check current ERG)
Initial isolation: ERG 152: isolate spill 25m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
Common Hazards of UN 2729
- Hexachlorobenzene is highly toxic by inhalation, ingestion or skin absorption.
- Dust or heated vapor can irritate the respiratory tract and contaminate clothing and equipment.
- Combustible solid; it may burn in a sustained fire but does not ignite readily.
- Fire can produce toxic and corrosive chlorinated decomposition products, including hydrogen chloride.
- Molten material can cause thermal burns and spread contamination.
- Runoff from fire control can pollute waterways and should be contained.
- Containers may rupture when heated.
Chemical Identity & Physical Properties
White crystalline solid with a faint aromatic odor. Sublimes at room temperature
| Also known as | HCBPerchlorobenzenePentachlorophenyl chlorideAnticarieJulin's carbon chloride |
| CAS Number | 118-74-1 |
| Appearance | White crystalline solid with a faint aromatic odor. Sublimes at room temperature. |
| Flash Point | Not applicable (combustible solid, but does not readily ignite) |
| Boiling Point | 322-326C (612-619F) with sublimation |
| Vapor Density | Not applicable (solid, but vapors heavier than air if volatilized) |
| Water Reactivity | No significant reaction with water, but essentially insoluble |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2729
Extinguishing Media
Dry chemical, CO2, water spray for cooling containers; foam acceptable for fire control
PPE Requirements
⚠️ Level A or B with SCBA required; avoid all skin contact with solid or molten material; chemical-resistant suit mandatory
Use SCBA and chemical-protective clothing that prevents skin contact; control contaminated clothing, tools and runoff.
Isolation & Evacuation
ERG 152: isolate spill 25m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 152).
First Actions for a UN 2729 Incident
- Call 911 and the emergency response number shown on the shipping papers.
- Keep unauthorized personnel away and deny entry to the spill or fire area.
- Stay upwind, uphill and upstream; avoid low areas where vapors or runoff may collect.
- Avoid breathing dust, vapor, mist or smoke; prevent skin and eye contact.
- Do not touch damaged containers or spilled material without appropriate PPE.
- Ventilate confined spaces only if personnel are trained, equipped and monitored.
- Use the ERG, SDS, shipping papers and air monitoring to set isolation, PPE and tactical decisions.
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📋 Copy & Share Field Card
UN 2729 — HexachlorobenzeneHAZMAT RADIO NOTE — UN 2729
Product: Hexachlorobenzene
Class 6 / Toxic / ERG 152
PPE: Level A or B with SCBA required; avoid all skin contact with solid or molten material; chemical-resistant suit mandatory
ISOLATION: ERG 152: isolate spill 25m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
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 2729 — Hexachlorobenzene
Class: 6 | Placard: Toxic | ERG Guide: 152
Appearance: White crystalline solid with a faint aromatic odor. Sublimes at room temperature.
Water Reactivity: No significant reaction with water, but essentially insoluble
Extinguishing: Dry chemical, CO2, water spray for cooling containers; foam acceptable for fire control
PPE: Level A or B with SCBA required; avoid all skin contact with solid or molten material; chemical-resistant suit mandatory
Isolation: ERG 152: isolate spill 25m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation
— Key Hazards —
• Hexachlorobenzene is highly toxic by inhalation, ingestion or skin absorption.
• Dust or heated vapor can irritate the respiratory tract and contaminate clothing and equipment.
• Combustible solid; it may burn in a sustained fire but does not ignite readily.
— First Actions —
• Call 911 and the emergency response number shown on the shipping papers.
• Keep unauthorized personnel away and deny entry to the spill or fire area.
• Stay upwind, uphill and upstream; avoid low areas where vapors or runoff may collect.
• Avoid breathing dust, vapor, mist or smoke; prevent skin and eye contact.
SOURCE: allfirefighter.com/hazmat/un/hexachlorobenzene-un-2729 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN2729 Hexachlorobenzene Cls6 ERG152 | allfirefighter.com/hazmat/un/hexachlorobenzene-un-2729SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/hexachlorobenzene-un-2729
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Frequently Asked Questions about UN 2729
UN 2729 is Hexachlorobenzene, regulated as a highly toxic chlorinated aromatic solid for transport and emergency response.
The main concern is a highly toxic chlorinated aromatic solid behavior plus exposure risk from dust, vapor, liquid or fire products.
Approach from upwind, isolate the area, keep nonessential people out and verify the exact product with shipping papers or SDS.
It does not react significantly with water, but runoff may carry persistent toxic contamination and should be contained.
Use SCBA and chemical-protective clothing that prevents skin contact; control contaminated clothing, tools and runoff.
Fire may produce toxic chlorinated smoke and corrosive gases; avoid downwind exposure and contain runoff.
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.