☣️ 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.
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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
| 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.
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
- 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, pyrophHAZMAT 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.
=== 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.
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
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Frequently Asked Questions about 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.
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.
Water reactivity: Reacts violently with water, generates flammable gases and heat. Do not use water.. Recommended extinguishing: Dry chemical, dry sand, vermiculite, metal-X powder. Do NOT use water, foam, CO2, or halogenated agents..
ERG Guide 135 recommendation: ERG 135: Isolate spill 25-50m all directions. If tank/rail car involved in fire, isolate 800m all directions and consider evacuation for 800m.
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.