☣️ UN 1560 • CLASS 6

UN 1560 — Arsenic trichloride

Placard: Toxic. ERG Guide 157. 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.

UN 1560 is Arsenic trichloride, a highly toxic and corrosive arsenic halide assigned to ERG Guide 157. It fumes in moist air and can release corrosive hydrogen halide fumes plus toxic arsenic contamination.

Hazard overview: UN 1560 presents toxic arsenic exposure, corrosive fume and water-reactivity hazards. Water contact can generate heat and dense toxic/corrosive fumes; responders should keep runoff controlled and avoid direct contact.

Response guidance: For a UN 1560 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 157. Establish incident command, isolate the area, stay upwind, prevent dust or vapor exposure, control runoff and choose entry or cleanup actions based on monitoring, SDS and local SOP.

Firefighter training notes: Training for UN 1560 should emphasize water-reactive toxic/corrosive fumes, arsenic contamination, air monitoring, dry-agent selection and decontamination. Common errors include applying water directly and entering fuming areas without SCBA. Use ERG 157, SDS and hazmat SOP.

Regulatory context: Arsenic trichloride is regulated as a toxic arsenic hazardous material. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by compound, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.

Storage & handling: Arsenic trichloride should be stored in tightly closed compatible containers in a cool, dry, well-ventilated secure area away from water, moisture, acids/bases where incompatible, oxidizers and heat. Protect containers from corrosion, leaks and unauthorized access.

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UN 1560 Quick Details

UN 1560
Product name: Arsenic trichloride
DOT Class: 6
Placard type: Toxic
ERG Guide: 157 (check current ERG)
Initial isolation: ERG 157: isolate spill 25-50m all directions; for large spill isolate 100m and consider evacuation 300m downwind; if tank/rail car involved in fire isolate 800m

Common Hazards of UN 1560

  • HIGHLY TOXIC and CORROSIVE; inhalation, ingestion or skin contact may cause severe or fatal injury.
  • Reacts with water or moist air to release corrosive hydrogen halide fumes and toxic arsenic compounds.
  • Reaction with water may generate heat and dense irritating fumes.
  • Vapors or fumes are heavier than air and may collect in low or confined areas.
  • Fire may produce irritating, corrosive and/or toxic gases.
  • Runoff may spread toxic and corrosive contamination.
  • Containers may rupture or fail when heated.

Chemical Identity & Physical Properties

Colorless to pale yellow oily liquid with a pungent, acrid odor. Fumes in moist air forming white clouds of hydrochloric acid and arsenic trioxide.

Also known asArsenous trichlorideArsenous chlorideButter of arsenicFuming liquid arsenic
CAS Number7784-34-1
AppearanceColorless to pale yellow oily liquid with a pungent, acrid odor. Fumes in moist air forming white clouds of hydrochloric acid and arsenic trioxide.
Flash PointNot applicable (non-flammable liquid)
Boiling Point130C (266F)
Vapor Density7.0 (much heavier than air)
Water ReactivityReacts violently with water producing toxic and corrosive hydrogen chloride gas and arsenic acid; generates significant heat
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 1560

Extinguishing Media

Use dry chemical, CO2, dry sand or other compatible dry media when directed by incident command. Do not apply water or foam directly to the material because water contact can release corrosive fumes and toxic arsenic contamination.

PPE Requirements

⚠️ Level A minimum for spill response; fully encapsulating suit with SCBA required; extreme toxicity hazard from both vapor and contact

Use positive-pressure SCBA and chemical-resistant protective clothing for vapor, fume, liquid or unknown exposure. Level A may be needed for close entry because both toxic arsenic and corrosive hydrogen halide fumes are possible.

Isolation & Evacuation

ERG 157: isolate spill 25-50m all directions; for large spill isolate 100m and consider evacuation 300m downwind; if tank/rail car involved in fire isolate 800m
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 157).

First Actions for a UN 1560 Incident

  • CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
  • Keep unauthorized personnel away.
  • Stay upwind, uphill and/or upstream.
  • Avoid breathing vapors, fumes, dust or mist and avoid all skin or eye contact.
  • Keep water and moisture away from the released material unless incident command confirms a compatible cooling or control use.
  • Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
  • Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
  • Isolate the spill or leak area and expand the perimeter if vapor, dust, fire involvement or unknown concentration is present.
  • Use ERG Guide 157, shipping papers, SDS, air monitoring and incident command for protective actions.
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📋 Copy & Share Field Card

UN 1560 — Arsenic trichloride
HAZMAT RADIO NOTE — UN 1560 Product: Arsenic trichloride Class 6 / Toxic / ERG 157 PPE: Level A minimum for spill response; fully encapsulating suit with SCBA required; extreme toxicity hazard from both vapor and contact ISOLATION: ERG 157: isolate spill 25-50m all directions; for large spill isolate 100m and consider evacuation 300m downwind; if tank/rail car involved in fire isolate 800m 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 1560 — Arsenic trichloride Class: 6 | Placard: Toxic | ERG Guide: 157 Appearance: Colorless to pale yellow oily liquid with a pungent, acrid odor. Fumes in moist air forming white clouds of hydrochloric acid and arsenic trioxide. Water Reactivity: Reacts violently with water producing toxic and corrosive hydrogen chloride gas and arsenic acid; generates significant heat Extinguishing: Use dry chemical, CO2, dry sand or other compatible dry media when directed by incident command. Do not apply water or foam directly to the material because water contact can release corrosive fumes and toxic arsenic contamination. PPE: Level A minimum for spill response; fully encapsulating suit with SCBA required; extreme toxicity hazard from both vapor and contact Isolation: ERG 157: isolate spill 25-50m all directions; for large spill isolate 100m and consider evacuation 300m downwind; if tank/rail car involved in fire isolate 800m — Key Hazards — • HIGHLY TOXIC and CORROSIVE; inhalation, ingestion or skin contact may cause severe or fatal injury. • Reacts with water or moist air to release corrosive hydrogen halide fumes and toxic arsenic compounds. • Reaction with water may generate heat and dense irritating fumes. — First Actions — • CALL 911. Then call the emergency response telephone number on the shipping paper, if available. • Keep unauthorized personnel away. • Stay upwind, uphill and/or upstream. • Avoid breathing vapors, fumes, dust or mist and avoid all skin or eye contact. SOURCE: allfirefighter.com/hazmat/un/arsenic-trichloride-un-1560 | Always use current ERG + SOP/SOGIC BRIEFING

Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.

SMS (short)
UN1560 Arsenic trichloride Cls6 ERG157 | allfirefighter.com/hazmat/un/arsenic-trichloride-un-1560SMS / 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/arsenic-trichloride-un-1560

Related UN Numbers in Class 6

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 1560

UN 1560 is Arsenic trichloride, a toxic hazardous material assigned to ERG Guide 157.

No. It is not normally flammable, but water reaction, toxic fumes and corrosive contamination are major hazards.

ERG Guide 157 applies to UN 1560 for initial isolation, protective actions and first response guidance.

UN 1560 presents toxic arsenic exposure, corrosive fume and water-reactivity hazards. Water contact can generate heat and dense toxic/corrosive fumes; responders should keep runoff controlled and avoid direct contact.

Use positive-pressure SCBA and chemical-resistant protective clothing for vapor, fume, liquid or unknown exposure. Level A may be needed for close entry because both toxic arsenic and corrosive hydrogen halide fumes are possible.

Do not apply water directly to the material unless incident command and SDS confirm a safe use, because water contact can release heat, corrosive fumes and toxic arsenic contamination.
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.