☣️ UN 1408 • CLASS 4
UN 1408 — Ferrosilicon
Placard: Dangerous When Wet. ERG Guide 139. 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.
Ferrosilicon is a highly reactive metal that can ignite on contact with water or moist air and produce toxic gases. It is typically stored in a dry environment.
Hazard overview: Ferrosilicon produces flammable and toxic gases on contact with water and may ignite on contact with water or moist air.
Response guidance: In case of fire or large spill, isolate the area at least 800m downwind during the day. Do not use water or foam.
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UN 1408 Quick Details
UN 1408
Product name: Ferrosilicon
DOT Class: 4
Placard type: Dangerous When Wet
ERG Guide: 139 (check current ERG)
Initial isolation: ERG 139: Initial isolation 50m in all directions; if fire or large spill, isolate 800m downwind during day
Common Hazards of UN 1408
- Produce flammable and toxic gases on contact with water.
- May ignite on contact with water or moist air.
- Some react vigorously or explosively on contact with water.
- May be ignited by heat, sparks or flames.
- May re-ignite after fire is extinguished.
- Some are transported in highly flammable liquids.
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
Chemical Identity & Physical Properties
Ferrosilicon is a gray to dark gray metallic solid with a crystalline or granular appearance and an odorless.
| Also known as | Ferrosilicon alloyIron silicon alloySilicon ironFerrosilicium |
| CAS Number | 8049-17-0 |
| Appearance | Gray to dark gray metallic solid with a crystalline or granular appearance. Odorless. Exists as lumps, granules, or powder at room temperature. |
| Flash Point | Not applicable (reacts with moisture to produce flammable hydrogen gas) |
| Boiling Point | Not applicable (solid alloy, decomposes/reacts rather than boils) |
| Vapor Density | Not applicable (solid material) |
| Water Reactivity | Reacts with water or moisture to produce flammable hydrogen gas and silane; reaction intensifies with heat and finely divided material |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1408
Extinguishing Media
Dry sand, dry chemical, soda ash; do not use water or foam
PPE Requirements
⚠️ Level B minimum recommended; SCBA required due to toxic gas evolution; chemical-resistant gloves and boots for handling
Level B minimum is recommended, including SCBA due to toxic gas evolution and chemical-resistant gloves and boots for handling.
Isolation & Evacuation
ERG 139: Initial isolation 50m in all directions; if fire or large spill, isolate 800m downwind during day
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 139).
First Actions for a UN 1408 Incident
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- 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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📋 Copy & Share Field Card
UN 1408 — FerrosiliconHAZMAT RADIO NOTE — UN 1408
Product: Ferrosilicon
Class 4 / Dangerous When Wet / ERG 139
PPE: Level B minimum recommended; SCBA required due to toxic gas evolution; chemical-resistant gloves and boots for handling
ISOLATION: ERG 139: Initial isolation 50m in all directions; if fire or large spill, isolate 800m downwind during day
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 1408 — Ferrosilicon
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 139
Appearance: Gray to dark gray metallic solid with a crystalline or granular appearance. Odorless. Exists as lumps, granules, or powder at room temperature.
Water Reactivity: Reacts with water or moisture to produce flammable hydrogen gas and silane; reaction intensifies with heat and finely divided material
Extinguishing: Dry sand, dry chemical, soda ash; do not use water or foam
PPE: Level B minimum recommended; SCBA required due to toxic gas evolution; chemical-resistant gloves and boots for handling
Isolation: ERG 139: Initial isolation 50m in all directions; if fire or large spill, isolate 800m downwind during day
— Key Hazards —
• Produce flammable and toxic gases on contact with water.
• May ignite on contact with water or moist air.
• Some react vigorously or explosively on contact with water.
— First Actions —
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
• 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/1408 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1408 Ferrosilicon Cls4 ERG139 | ERG 139: Initial isolation 50m in all directions; if fire or large spill, isolat | allfirefighter.com/hazmat/un/1408SMS / 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/ferrosilicon-un-1408
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Frequently Asked Questions about UN 1408
Yes, Ferrosilicon is flammable and can ignite on contact with water or moist air.
Ferrosilicon reacts with water or moisture to produce flammable hydrogen gas and silane.
Handle Ferrosilicon with Level B minimum PPE, including SCBA, and avoid moisture contact with skin or equipment.
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.