☣️ UN 1403 • CLASS 4
UN 1403 — Calcium cyanamide, with more than 0.1% calcium carbide
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.
Calcium cyanamide is a highly reactive substance that can produce flammable gases when exposed to water. It is essential to handle this substance with extreme caution.
Hazard overview: Calcium cyanamide can ignite spontaneously on contact with moisture, producing flammable gases. It may also react violently with water, releasing acetylene gas.
Response guidance: In case of a spill, isolate the area 25m in all directions and evacuate 800m downwind if a fire involves large quantities. Use dry chemical, dry sand, or soda ash to extinguish the fire.
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UN 1403 Quick Details
UN 1403
Product name: Calcium cyanamide, with more than 0.1% calcium carbide
DOT Class: 4
Placard type: Dangerous When Wet
ERG Guide: 138 (check current ERG)
Initial isolation: ERG 138: Isolate spill 25m in all directions; evacuate 800m downwind if fire involves large quantities
Common Hazards of UN 1403
- 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
Calcium cyanamide appears as a gray to black crystalline solid or powder with a characteristic odor.
| Also known as | Calcium cyanamideCaCN2Lime nitrogenNitrolimeCyanamide calcium saltAlzodef |
| CAS Number | 156-62-7 |
| Appearance | Gray to black crystalline solid or powder with a characteristic odor. Commercial grades may appear as granules or prills. |
| Flash Point | Not applicable (solid that reacts with water to produce flammable gas) |
| Boiling Point | Not applicable (decomposes above 1150°C/2102°F) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts with water to produce acetylene gas (flammable) due to calcium carbide content; may ignite spontaneously on contact with moisture |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1403
Extinguishing Media
Dry chemical, dry sand, soda ash; DO NOT use water or foam-based agents
PPE Requirements
⚠️ Level B minimum with SCBA; chemical-resistant suit; nitrile or neoprene gloves; avoid moisture exposure
Level B minimum personal protective equipment (PPE) is required, including a self-contained breathing apparatus (SCBA), chemical-resistant suit, and nitrile or neoprene gloves.
Isolation & Evacuation
ERG 138: Isolate spill 25m in all directions; evacuate 800m downwind if fire involves large quantities
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 138).
First Actions for a UN 1403 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
- Consider initial downwind evacuation for at least 300 meters (1000 feet).
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📋 Copy & Share Field Card
UN 1403 — Calcium cyanamide, with more than 0.1% cHAZMAT RADIO NOTE — UN 1403
Product: Calcium cyanamide, with more than 0.1% calcium carbide
Class 4 / Dangerous When Wet / ERG 138
PPE: Level B minimum with SCBA; chemical-resistant suit; nitrile or neoprene gloves; avoid moisture exposure
ISOLATION: ERG 138: Isolate spill 25m in all directions; evacuate 800m downwind if fire involves large quantities
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 1403 — Calcium cyanamide, with more than 0.1% calcium carbide
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 138
Appearance: Gray to black crystalline solid or powder with a characteristic odor. Commercial grades may appear as granules or prills.
Water Reactivity: Reacts with water to produce acetylene gas (flammable) due to calcium carbide content; may ignite spontaneously on contact with moisture
Extinguishing: Dry chemical, dry sand, soda ash; DO NOT use water or foam-based agents
PPE: Level B minimum with SCBA; chemical-resistant suit; nitrile or neoprene gloves; avoid moisture exposure
Isolation: ERG 138: Isolate spill 25m in all directions; evacuate 800m downwind if fire involves large quantities
— 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 —
• 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/1403 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1403 Calcium cyanamide, with more than 0.1% calcium carbide Cls4 ERG138 | allfirefighter.com/hazmat/un/1403SMS / 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/calcium-cyanamide-with-more-un-1403
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Frequently Asked Questions about UN 1403
Yes, UN 1403 can produce flammable gases on contact with water.
Yes, UN 1403 may ignite spontaneously on contact with moisture.
Avoid exposure to moisture when handling UN 1403.
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.