☣️ UN 2844 • CLASS 4
UN 2844 — Calcium manganese silicon
Placard: Dangerous When Wet. ERG Guide 138. 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 2844 Quick Details
UN 2844
Product name: Calcium manganese silicon
DOT Class: 4
Placard type: Dangerous When Wet
ERG Guide: 138 (check current ERG)
Initial isolation: ERG 138: Initial isolation 60m (200 ft) in all directions. For large spills, isolate 150m (500 ft) in all directions. Keep material dry and away from water sources.
Common Hazards of UN 2844
- Produce flammable 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.
- Runoff may create fire or explosion hazard.
- Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
Chemical Identity & Physical Properties
| Also known as | Calcium manganese silicon alloySilico-manganese-calciumCa-Mn-Si alloyFerroalloy calcium manganese silicon |
| Appearance | Silvery-gray to dark gray metallic solid or granules with a metallic appearance. Odorless metallic alloy typically supplied as lumps, granules, or powder. |
| Flash Point | Not applicable (metallic solid) |
| Boiling Point | Not applicable (metallic alloy, decomposes at high temperature) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts with water or moisture to produce flammable hydrogen gas and may ignite spontaneously. Violent reaction with water produces heat and flammable gases. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2844
Extinguishing Media
Dry sand, dry chemical, soda ash, or dry limestone. Do not use water, foam, or CO2.
PPE Requirements
⚠️ Level B minimum recommended. SCBA required in confined spaces or fire conditions. Chemical-resistant gloves and protective clothing to prevent skin contact with moisture-activated material.
Isolation & Evacuation
ERG 138: Initial isolation 60m (200 ft) in all directions. For large spills, isolate 150m (500 ft) in all directions. Keep material dry and away from water sources.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 138).
First Actions for a UN 2844 Incident
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- 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
- Consider initial downwind evacuation for at least 300 meters (1000 feet).
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UN 2844 — Calcium manganese siliconHAZMAT RADIO NOTE — UN 2844
Product: Calcium manganese silicon
Class 4 / Dangerous When Wet / ERG 138
PPE: Level B minimum recommended. SCBA required in confined spaces or fire conditions. Chemical-resistant gloves and protective clothing to prevent skin contact with moisture-activated material.
ISOLATION: ERG 138: Initial isolation 60m (200 ft) in all directions. For large spills, isolate 150m (500 ft) in all directions. Keep material dry and away from water sources.
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 2844 — Calcium manganese silicon
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 138
Appearance: Silvery-gray to dark gray metallic solid or granules with a metallic appearance. Odorless metallic alloy typically supplied as lumps, granules, or powder.
Water Reactivity: Reacts with water or moisture to produce flammable hydrogen gas and may ignite spontaneously. Violent reaction with water produces heat and flammable gases.
Extinguishing: Dry sand, dry chemical, soda ash, or dry limestone. Do not use water, foam, or CO2.
PPE: Level B minimum recommended. SCBA required in confined spaces or fire conditions. Chemical-resistant gloves and protective clothing to prevent skin contact with moisture-activated material.
Isolation: ERG 138: Initial isolation 60m (200 ft) in all directions. For large spills, isolate 150m (500 ft) in all directions. Keep material dry and away from water sources.
— Key Hazards —
• Produce flammable 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 —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/2844 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2844 Calcium manganese silicon Cls4 ERG138 | allfirefighter.com/hazmat/un/2844SMS / 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/2844
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Frequently Asked Questions about UN 2844
Produce flammable 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. Runoff may create fire or explosion hazard. Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level B minimum recommended. SCBA required in confined spaces or fire conditions. Chemical-resistant gloves and protective clothing to prevent skin contact with moisture-activated material.
Water reactivity: Reacts with water or moisture to produce flammable hydrogen gas and may ignite spontaneously. Violent reaction with water produces heat and flammable gases.. Recommended extinguishing: Dry sand, dry chemical, soda ash, or dry limestone. Do not use water, foam, or CO2..
ERG Guide 138 recommendation: ERG 138: Initial isolation 60m (200 ft) in all directions. For large spills, isolate 150m (500 ft) in all directions. Keep material dry and away from water sources.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 138 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.