☣️ UN 1780 • CLASS 8

UN 1780 — Fumaryl chloride

Placard: Corrosive. ERG Guide 156. 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 1780 is Fumaryl chloride, a toxic corrosive acid chloride assigned to ERG Guide 156. It fumes in moist air and can release heat plus dense hydrogen chloride fumes.

Hazard overview: UN 1780 presents corrosive vapor, toxic exposure, water-reaction and combustible liquid hazards. Avoid water contact with product and contain acidic runoff.

Response guidance: For a UN 1780 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 156. Establish incident command, isolate the area, stay upwind, prevent incompatible contact, control runoff and choose entry or fire-control actions based on monitoring, SDS and local SOP.

Firefighter training notes: Training for UN 1780 should emphasize corrosive exposure routes, water or oxidizer incompatibility where applicable, air monitoring, PPE selection, decontamination and runoff containment. Use ERG 156, SDS and local SOP.

Regulatory context: Fumaryl chloride is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by concentration, formulation, 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: Fumaryl chloride should be stored in tightly closed compatible containers in a cool, dry, well-ventilated area away from water, moisture, bases, oxidizers/reducing agents where incompatible, heat and unauthorized access. Protect containers from corrosion, leakage and contamination.

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UN 1780 Quick Details

UN 1780
Product name: Fumaryl chloride
DOT Class: 8
Placard type: Corrosive
ERG Guide: 156 (check current ERG)
Initial isolation: ERG 156: isolate spill 25-50m; if tank/rail car involved in fire, isolate 800m all directions

Common Hazards of UN 1780

  • TOXIC and CORROSIVE acid chloride; inhalation, ingestion or skin/eye contact may cause severe injury.
  • Reacts with water or moist air, releasing heat and corrosive hydrogen chloride fumes.
  • Combustible liquid: may burn under fire conditions.
  • Vapors 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 or contaminated with water.

Chemical Identity & Physical Properties

Colorless to pale yellow liquid with a pungent, acrid odor. Fumes in moist air due to hydrolysis.

Also known asFumaroyl dichlorideFumaric acid dichloridetrans-1,2-Ethylenedicarboxylic acid dichloride2-Butenedioyl dichloride
CAS Number627-63-4
AppearanceColorless to pale yellow liquid with a pungent, acrid odor. Fumes in moist air due to hydrolysis.
Flash Point102C (216F)
Boiling Point160C (320F) with decomposition
Vapor Density5.3 (much heavier than air)
Water ReactivityReacts violently with water producing hydrochloric acid and fumaric acid; avoid water contact
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 1780

Extinguishing Media

Use dry chemical, CO2, dry sand, soda ash, lime or other compatible dry media when directed by incident command. Avoid water or foam directly on product unless SDS and incident command confirm a safe use; cool nearby containers from a protected distance.

PPE Requirements

⚠️ Level B minimum with full face SCBA; acid-resistant suit required; avoid all skin/eye contact

Use positive-pressure SCBA for vapor, fume, fire or confined-space exposure. Chemical-resistant gloves, boots, eye/face protection and protective clothing should be selected from SDS; Level A may be needed for close entry or unknown concentrations.

Isolation & Evacuation

ERG 156: isolate spill 25-50m; if tank/rail car involved in fire, isolate 800m all directions
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 156).

First Actions for a UN 1780 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, mist or spray and avoid skin or eye contact.
  • Keep water and moisture away from released product 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, water reaction or unknown concentration is present.
  • Use ERG Guide 156, shipping papers, SDS, air monitoring and incident command for protective actions.
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📋 Copy & Share Field Card

UN 1780 — Fumaryl chloride
HAZMAT RADIO NOTE — UN 1780 Product: Fumaryl chloride Class 8 / Corrosive / ERG 156 PPE: Level B minimum with full face SCBA; acid-resistant suit required; avoid all skin/eye contact ISOLATION: ERG 156: isolate spill 25-50m; if tank/rail car involved in fire, isolate 800m all directions 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 1780 — Fumaryl chloride Class: 8 | Placard: Corrosive | ERG Guide: 156 Appearance: Colorless to pale yellow liquid with a pungent, acrid odor. Fumes in moist air due to hydrolysis. Water Reactivity: Reacts violently with water producing hydrochloric acid and fumaric acid; avoid water contact Extinguishing: Use dry chemical, CO2, dry sand, soda ash, lime or other compatible dry media when directed by incident command. Avoid water or foam directly on product unless SDS and incident command confirm a safe use; cool nearby containers from a protected distance. PPE: Level B minimum with full face SCBA; acid-resistant suit required; avoid all skin/eye contact Isolation: ERG 156: isolate spill 25-50m; if tank/rail car involved in fire, isolate 800m all directions — Key Hazards — • TOXIC and CORROSIVE acid chloride; inhalation, ingestion or skin/eye contact may cause severe injury. • Reacts with water or moist air, releasing heat and corrosive hydrogen chloride fumes. • Combustible liquid: may burn under fire conditions. — 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, mist or spray and avoid skin or eye contact. SOURCE: allfirefighter.com/hazmat/un/fumaryl-chloride-un-1780 | Always use current ERG + SOP/SOGIC BRIEFING

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

SMS (short)
UN1780 Fumaryl chloride Cls8 ERG156 | allfirefighter.com/hazmat/un/fumaryl-chloride-un-1780SMS / 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/fumaryl-chloride-un-1780

Related UN Numbers in Class 8

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 1780

UN 1780 is Fumaryl chloride, a hazardous material assigned to ERG Guide 156.

It is combustible but not normally highly flammable; water reaction and toxic/corrosive fumes are the main hazards.

ERG Guide 156 applies to UN 1780 for initial isolation, protective actions and first response guidance.

UN 1780 presents corrosive vapor, toxic exposure, water-reaction and combustible liquid hazards. Avoid water contact with product and contain acidic runoff.

Use positive-pressure SCBA for vapor, fume, fire or confined-space exposure. Chemical-resistant gloves, boots, eye/face protection and protective clothing should be selected from SDS; Level A may be needed for close entry or unknown concentrations.

Water or moist air can generate heat and toxic/corrosive fumes. Direct water application should follow ERG, SDS and incident command because reaction or runoff can worsen exposure.
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.