☣️ UN 3391 • CLASS 4
UN 3391 — Organometallic substance, solid, pyrophoric
Placard: Spontaneously Combustible. ERG Guide 135. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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.
Advertisement
UN 3391 Quick Details
UN 3391
Product name: Organometallic substance, solid, pyrophoric
DOT Class: 4
Placard type: Spontaneously Combustible
ERG Guide: 135 (check current ERG)
Initial isolation: ERG 135: Isolate spill 25m all directions. Large spill: initial isolation 100m, protective action 300m downwind.
Common Hazards of UN 3391
- 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 solidOrganometallic compound solid pyrophoricMetal-organic pyrophoric solid |
| Appearance | Solid material of varying color depending on specific compound. May appear as powder, granules, or crystalline solid. Ignites spontaneously when exposed to air at room temperature. |
| Flash Point | Not applicable (ignites spontaneously in air) |
| Boiling Point | Varies by specific compound |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts with moisture, may ignite or produce flammable gases. Keep completely dry. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3391
Extinguishing Media
Dry sand, dry chemical, soda ash. NO water, NO foam, NO CO2
PPE Requirements
⚠️ Level A or B with SCBA required. Full body protection against pyrophoric fire. Heat-resistant gloves essential.
Isolation & Evacuation
ERG 135: Isolate spill 25m all directions. Large spill: initial isolation 100m, protective action 300m downwind.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 135).
First Actions for a UN 3391 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
Advertisement
📋 Copy & Share Field Card
UN 3391 — Organometallic substance, solid, pyrophoHAZMAT RADIO NOTE — UN 3391
Product: Organometallic substance, solid, pyrophoric
Class 4 / Spontaneously Combustible / ERG 135
PPE: Level A or B with SCBA required. Full body protection against pyrophoric fire. Heat-resistant gloves essential.
ISOLATION: ERG 135: Isolate spill 25m all directions. Large spill: initial isolation 100m, protective action 300m downwind.
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 3391 — Organometallic substance, solid, pyrophoric
Class: 4 | Placard: Spontaneously Combustible | ERG Guide: 135
Appearance: Solid material of varying color depending on specific compound. May appear as powder, granules, or crystalline solid. Ignites spontaneously when exposed to air at room temperature.
Water Reactivity: Reacts with moisture, may ignite or produce flammable gases. Keep completely dry.
Extinguishing: Dry sand, dry chemical, soda ash. NO water, NO foam, NO CO2
PPE: Level A or B with SCBA required. Full body protection against pyrophoric fire. Heat-resistant gloves essential.
Isolation: ERG 135: Isolate spill 25m all directions. Large spill: initial isolation 100m, protective action 300m downwind.
— 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/3391 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3391 Organometallic substance, solid, pyrophoric Cls4 ERG135 | allfirefighter.com/hazmat/un/3391SMS / 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/3391
Advertisement
Frequently Asked Questions about UN 3391
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 body protection against pyrophoric fire. Heat-resistant gloves essential.
Water reactivity: Reacts with moisture, may ignite or produce flammable gases. Keep completely dry.. Recommended extinguishing: Dry sand, dry chemical, soda ash. NO water, NO foam, NO CO2.
ERG Guide 135 recommendation: ERG 135: Isolate spill 25m all directions. Large spill: initial isolation 100m, protective action 300m downwind.
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.