☣️ UN 1402 • CLASS 4
UN 1402 — Calcium carbide
Placard: Dangerous When Wet. ERG Guide 138. 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.
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.
Advertisement
UN 1402 Quick Details
UN 1402
Product name: Calcium carbide
DOT Class: 4
Placard type: Dangerous When Wet
ERG Guide: 138 (check current ERG)
Initial isolation: ERG 138: isolate spill area minimum 25m (80ft) all directions; if fire, isolate 800m (0.5 mile) and evacuate
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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1402
Extinguishing Media
DO NOT USE WATER OR FOAM; use dry sand, dry chemical, or soda ash only
PPE Requirements
⚠️ Level B minimum with SCBA; full protective clothing due to reactivity hazard and acetylene generation
Level B minimum PPE with SCBA is required, including full protective clothing due to reactivity hazard and acetylene generation.
Isolation & Evacuation
ERG 138: isolate spill area minimum 25m (80ft) all directions; if fire, isolate 800m (0.5 mile) and evacuate
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 138).
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).
Advertisement
📋 Copy & Share Field Card
UN 1402 — Calcium carbideHAZMAT RADIO NOTE — UN 1402
Product: Calcium carbide
Class 4 / Dangerous When Wet / ERG 138
PPE: Level B minimum with SCBA; full protective clothing due to reactivity hazard and acetylene generation
ISOLATION: ERG 138: isolate spill area minimum 25m (80ft) all directions; if fire, isolate 800m (0.5 mile) and evacuate
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 1402 — Calcium carbide
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 138
Appearance: Grayish-black or brown crystalline solid with a garlic-like odor when pure. Commercial grades appear as irregular hard lumps.
Water Reactivity: Reacts vigorously with water producing flammable acetylene gas and heat; may ignite spontaneously
Extinguishing: DO NOT USE WATER OR FOAM; use dry sand, dry chemical, or soda ash only
PPE: Level B minimum with SCBA; full protective clothing due to reactivity hazard and acetylene generation
Isolation: ERG 138: isolate spill area minimum 25m (80ft) all directions; if fire, isolate 800m (0.5 mile) and evacuate
— 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/1402 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1402 Calcium carbide Cls4 ERG138 | ERG 138: isolate spill area minimum 25m (80ft) all directions; if fire, isolate | allfirefighter.com/hazmat/un/1402SMS / 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-carbide-un-1402
Advertisement
Frequently Asked Questions about UN 1402
Yes, Calcium carbide produces flammable gases on contact with water.
No, water will react vigorously with Calcium carbide producing flammable acetylene gas and heat.
Level B minimum PPE with SCBA, including full protective clothing due to reactivity hazard and acetylene generation.
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.