☣️ UN 3394 • CLASS 4

Organometallic substance, liquid, pyrophoric, waterreactive

Placard: Spontaneously Combustible. 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 3394
Class: 4
Placard type: Spontaneously Combustible
ERG: Guide 135 (check current ERG)
Isolation: ERG 135: Isolate spill 25-50m all directions. If tank/rail car involved in fire, isolate 800m all directions and consider evacuation for 800m.
Chemical & Response Details
Also known asPyrophoric organometallic liquidWater-reactive organometallic compoundOrganometallic reagentMetal alkyl compound
AppearanceTypically colorless to pale yellow liquid with pungent or distinctive odor. Highly reactive, spontaneously ignites in air and reacts violently with water. Often used as specialized chemical reagents.
Flash PointNot applicable (pyrophoric, spontaneously ignites)
Boiling PointVaries by specific compound (typically 50-150C range)
Vapor DensityGreater than 1 (heavier than air)
Water ReactivityReacts violently with water, generates flammable gases and heat. Do not use water.
ExtinguishingDry chemical, dry sand, vermiculite, metal-X powder. Do NOT use water, foam, CO2, or halogenated agents.
PPE⚠️ Level A or B with SCBA required. Full chemical-resistant suit, gloves rated for pyrophoric materials. Handle only in inert atmosphere.
IsolationERG 135: Isolate spill 25-50m all directions. If tank/rail car involved in fire, isolate 800m all directions and consider evacuation for 800m.
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
  • Flammable/combustible material.
  • May ignite on contact with moist air or moisture.
  • May burn rapidly with flare-burning effect.
  • Some react vigorously or explosively on contact with water.
  • Some may decompose explosively when heated or involved in a fire.
  • May re-ignite after fire is extinguished.
  • Runoff may create fire or explosion hazard.
  • Containers may explode when heated.
First actions (field-minded)
  • CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
  • Stay upwind, uphill and/or upstream.
  • Keep unauthorized personnel away.
  • 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 3394 — Organometallic substance, liquid, pyroph
HAZMAT RADIO NOTE — UN 3394 Product: Organometallic substance, liquid, pyrophoric, waterreactive Class 4 / Spontaneously Combustible / ERG 135 PPE: Level A or B with SCBA required. Full chemical-resistant suit, gloves rated for pyrophoric materials. Handle only in inert atmosphere. ISOLATION: ERG 135: Isolate spill 25-50m all directions. If tank/rail car involved in fire, isolate 800m all directions and consider evacuation for 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 3394 — Organometallic substance, liquid, pyrophoric, waterreactive Class: 4 | Placard: Spontaneously Combustible | ERG Guide: 135 Appearance: Typically colorless to pale yellow liquid with pungent or distinctive odor. Highly reactive, spontaneously ignites in air and reacts violently with water. Often used as specialized chemical reagents. Water Reactivity: Reacts violently with water, generates flammable gases and heat. Do not use water. Extinguishing: Dry chemical, dry sand, vermiculite, metal-X powder. Do NOT use water, foam, CO2, or halogenated agents. PPE: Level A or B with SCBA required. Full chemical-resistant suit, gloves rated for pyrophoric materials. Handle only in inert atmosphere. Isolation: ERG 135: Isolate spill 25-50m all directions. If tank/rail car involved in fire, isolate 800m all directions and consider evacuation for 800m. — Key Hazards — • Flammable/combustible material. • May ignite on contact with moist air or moisture. • May burn rapidly with flare-burning effect. — First Actions — • CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper • Stay upwind, uphill and/or upstream. • Keep unauthorized personnel away. • 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/3394 | 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)
UN3394 Organometallic substance, liquid, pyrophoric, waterreactive Cls4 ERG135 | allfirefighter.com/hazmat/un/3394SMS / 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/3394
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

Flammable/combustible material. May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard. Containers may explode when heated.

CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Stay upwind, uphill and/or upstream. Keep unauthorized personnel away.

Level A or B with SCBA required. Full chemical-resistant suit, gloves rated for pyrophoric materials. Handle only in inert atmosphere.

No. This is a training/quick-reference aid only. Always consult the current ERG Guide 135 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.