☣️ UN 3394 • CLASS 4

UN 3394 — Organometallic substance, liquid, pyrophoric, waterreactive

Placard: Spontaneously Combustible. ERG Guide 135. 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.

Organometallic substances, such as UN 3394, are highly reactive and spontaneously ignite in air. They are often used as specialized chemical reagents.

Hazard overview: UN 3394 is a flammable/combustible material that may ignite on contact with moist air or moisture. It generates flammable gases and heat when reacting with water.

Response guidance: In case of emergency, evacuate the area and call the fire department. Use dry chemical, dry sand, vermiculite, or metal-X powder to extinguish the fire.

UN 3394 Quick Details

UN 3394

Product name: Organometallic substance, liquid, pyrophoric, waterreactive

DOT Class: 4

Placard type: Spontaneously Combustible

ERG Guide: 135 (check current ERG)

Initial 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.

Common Hazards of UN 3394

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.

Chemical Identity & Physical Properties

UN 3394 is typically a colorless to pale yellow liquid with a pungent or distinctive odor.

Also known as	Pyrophoric organometallic liquidWater-reactive organometallic compoundOrganometallic reagentMetal alkyl compound
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.
Flash Point	Not applicable (pyrophoric, spontaneously ignites)
Boiling Point	Varies by specific compound (typically 50-150C range)
Vapor Density	Greater than 1 (heavier than air)
Water Reactivity	Reacts violently with water, generates flammable gases and heat. Do not use water.

Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 3394

Extinguishing Media

Dry chemical, dry sand, vermiculite, metal-X powder. Do NOT use water, foam, CO2, or halogenated agents.

PPE Requirements

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

Wear Level A or B personal protective equipment (PPE) with a self-contained breathing apparatus (SCBA) and a full chemical-resistant suit, gloves rated for pyrophoric materials.

Isolation & Evacuation

ERG 135: Isolate spill 25-50m all directions. If tank/rail car involved in fire, isolate 800m all directions and consider evacuation for 800m.

Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 135).

First Actions for a UN 3394 Incident

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

📋 Copy & Share Field Card

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 — • 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. 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.

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.

Open in Messages WhatsApp

⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/organometallic-substance-liquid-pyrophoric-un-3394

Related UN Numbers in Class 4

Open Class Guide →Hazmat Hub →

UN 1183 UN 1242 UN 1295 UN 1309 UN 1310 UN 1312 UN 1313 UN 1314 UN 1318 UN 1320 UN 1321 UN 1322

Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.

Frequently Asked Questions about UN 3394

Yes, UN 3394 is a flammable/combustible material.

No, do not use water, as it reacts violently with UN 3394 and generates flammable gases and heat.

Wear Level A or B PPE with a SCBA and a full chemical-resistant suit, gloves rated for pyrophoric materials.

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.