☣️ UN 1017 • CLASS 2

UN 1017 — Chlorine

Placard: Toxic Gas. ERG Guide 124. 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 1017 Quick Details

UN 1017
Product name: Chlorine
DOT Class: 2
Placard type: Toxic Gas
ERG Guide: 124 (check current ERG)
Initial isolation: ERG 124: isolate 150m all directions as immediate precaution; evacuate 800m downwind if large spill

Common Hazards of UN 1017

  • 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 asMolecular chlorineCl2BertholiteDichlorine
CAS Number7782-50-5
AppearanceGreenish-yellow gas with a pungent, irritating odor detectable at very low concentrations. Shipped as a liquefied compressed gas.
Flash PointNot applicable (non-flammable gas)
Boiling Point-34C (-29F)
Vapor Density2.5 (heavier than air)
Water ReactivityReacts with water to form hypochlorous and hydrochloric acids; corrosive solution
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 1017

Extinguishing Media

Not applicable for extinguishment; use water spray to reduce vapors; do not direct water at leak

PPE Requirements

⚠️ Level A required for vapor concentrations; positive pressure SCBA and chemical-resistant suit mandatory

Isolation & Evacuation

ERG 124: isolate 150m all directions as immediate precaution; evacuate 800m downwind if large spill
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 124).

First Actions for a UN 1017 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 1017 — Chlorine
HAZMAT RADIO NOTE — UN 1017 Product: Chlorine Class 2 / Toxic Gas / ERG 124 PPE: Level A required for vapor concentrations; positive pressure SCBA and chemical-resistant suit mandatory ISOLATION: ERG 124: isolate 150m all directions as immediate precaution; evacuate 800m downwind if large spill 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 1017 — Chlorine Class: 2 | Placard: Toxic Gas | ERG Guide: 124 Appearance: Greenish-yellow gas with a pungent, irritating odor detectable at very low concentrations. Shipped as a liquefied compressed gas. Water Reactivity: Reacts with water to form hypochlorous and hydrochloric acids; corrosive solution Extinguishing: Not applicable for extinguishment; use water spray to reduce vapors; do not direct water at leak PPE: Level A required for vapor concentrations; positive pressure SCBA and chemical-resistant suit mandatory Isolation: ERG 124: isolate 150m all directions as immediate precaution; evacuate 800m downwind if large spill — 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/1017 | 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)
UN1017 Chlorine Cls2 ERG124 | ERG 124: isolate 150m all directions as immediate precaution; evacuate 800m down | allfirefighter.com/hazmat/un/1017SMS / 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/1017

Related UN Numbers in Class 2

Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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Frequently Asked Questions about UN 1017

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 for vapor concentrations; positive pressure SCBA and chemical-resistant suit mandatory

Water reactivity: Reacts with water to form hypochlorous and hydrochloric acids; corrosive solution. Recommended extinguishing: Not applicable for extinguishment; use water spray to reduce vapors; do not direct water at leak.

ERG Guide 124 recommendation: ERG 124: isolate 150m all directions as immediate precaution; evacuate 800m downwind if large spill

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.