☣️ UN 1402 • CLASS 4
Calcium carbide
Placard: Dangerous When Wet. 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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Quick details
UN 1402
Class: 4
Placard type: Dangerous When Wet
ERG: Guide 138 (check current ERG)
Isolation: ERG 138: isolate spill area minimum 25m (80ft) all directions; if fire, isolate 800m (0.5 mile) and evacuate
Chemical & Response Details
| 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 |
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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
First actions (field-minded)
- 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 1402 — Calcium carbide HAZMAT 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 —
• 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/1402 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
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. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/1402
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FAQ
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 with SCBA; full protective clothing due to reactivity hazard and acetylene generation
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.