UN 1402 — Calcium carbide
Placard: Dangerous When Wet. ERG Guide 138. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Calcium carbide is a grayish-black or brown crystalline solid with a garlic-like odor when pure. It is highly reactive and requires proper handling and storage.
Hazard overview: Calcium carbide produces flammable gases on contact with water and may ignite spontaneously. It also reacts vigorously with water, producing heat and flammable acetylene gas.
Response guidance: In case of a spill, isolate the area at least 25 meters in all directions. If a fire occurs, isolate the area 800 meters and evacuate.
UN 1402 Quick Details
Common Hazards of UN 1402
- 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 carbide is a grayish-black or brown crystalline solid with a garlic-like odor when pure, appearing as irregular hard lumps.
| Also known as | Calcium acetylideCalcium dicarbideAcetylenogenCarbide |
| CAS Number | 75-20-7 |
| Appearance | Grayish-black or brown crystalline solid with a garlic-like odor when pure. Commercial grades appear as irregular hard lumps. |
| Flash Point | Not applicable (reacts with water to produce flammable acetylene gas) |
| Boiling Point | Not applicable (decomposes above 2300C/4172F) |
| Vapor Density | Not applicable (solid, but produces acetylene gas with vapor density 0.9) |
| Water Reactivity | Reacts vigorously with water producing flammable acetylene gas and heat; may ignite spontaneously |
Fireground Response Guidance — UN 1402
Extinguishing Media
PPE Requirements
Level B minimum PPE with SCBA is required, including full protective clothing due to reactivity hazard and acetylene generation.
Isolation & Evacuation
First Actions for a UN 1402 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).
📋 Copy & Share Field Card
UN 1402 — Calcium carbideUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.