☣️ UN 1591 • CLASS 6

o-Dichlorobenzene

Placard: Toxic. 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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Quick details
UN 1591
Class: 6
Placard type: Toxic
ERG: Guide 152 (check current ERG)
Isolation: ERG 152: Isolate spill 25-50m in all directions; for large spills isolate 100m and evacuate downwind 300m initially.
Chemical & Response Details
Also known as1,2-Dichlorobenzeneortho-DichlorobenzeneODCBChlorobenDowtherm E
CAS Number95-50-1
AppearanceClear to pale yellow liquid with a pleasant, aromatic odor similar to mothballs. Denser than water and insoluble in water.
Flash Point66°C (151°F)
Boiling Point180°C (356°F)
Vapor Density5.05 (heavier than air)
Water ReactivityNo significant reaction with water; insoluble and will sink.
ExtinguishingAlcohol-resistant foam, dry chemical, CO2, water spray for cooling containers
PPE⚠️ Level B minimum with SCBA and chemical-resistant suit; prevent any skin contact due to absorption hazard.
IsolationERG 152: Isolate spill 25-50m in all directions; for large spills isolate 100m and evacuate downwind 300m initially.
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
  • Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.
  • Contact with molten substance may cause severe burns to skin and eyes.
  • Avoid any skin contact.
  • Fire may produce irritating, corrosive and/or toxic gases.
  • Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
  • Combustible material: may burn but does not ignite readily.
  • Containers may explode when heated.
  • Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
First actions (field-minded)
  • 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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UN 1591 — o-Dichlorobenzene
HAZMAT RADIO NOTE — UN 1591 Product: o-Dichlorobenzene Class 6 / Toxic / ERG 152 PPE: Level B minimum with SCBA and chemical-resistant suit; prevent any skin contact due to absorption hazard. ISOLATION: ERG 152: Isolate spill 25-50m in all directions; for large spills isolate 100m and evacuate downwind 300m initially. ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO

Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.

SMS WhatsApp
=== IC HAZMAT BRIEFING === UN 1591 — o-Dichlorobenzene Class: 6 | Placard: Toxic | ERG Guide: 152 Appearance: Clear to pale yellow liquid with a pleasant, aromatic odor similar to mothballs. Denser than water and insoluble in water. Water Reactivity: No significant reaction with water; insoluble and will sink. Extinguishing: Alcohol-resistant foam, dry chemical, CO2, water spray for cooling containers PPE: Level B minimum with SCBA and chemical-resistant suit; prevent any skin contact due to absorption hazard. Isolation: ERG 152: Isolate spill 25-50m in all directions; for large spills isolate 100m and evacuate downwind 300m initially. — Key Hazards — • Highly toxic, may be fatal if inhaled, ingested or absorbed through skin. • Contact with molten substance may cause severe burns to skin and eyes. • Avoid any skin contact. — 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/1591 | Always use current ERG + SOP/SOGIC BRIEFING

Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.

SMS (short)
UN1591 o-Dichlorobenzene Cls6 ERG152 | ERG 152: Isolate spill 25-50m in all directions; for large spills isolate 100m a | allfirefighter.com/hazmat/un/1591SMS / 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/1591
Related UN numbers (same class)
Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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FAQ

Highly toxic, may be fatal if inhaled, ingested or absorbed through skin. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental Combustible material: may burn but does not ignite readily. Containers may explode when heated. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.

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 B minimum with SCBA and chemical-resistant suit; prevent any skin contact due to absorption hazard.

No. This is a training/quick-reference aid only. Always consult the current ERG Guide 152 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.