☣️ UN 3553 • CLASS 2
UN 3553 — Disilane
Placard: Toxic Gas / Flammable Gas. ERG Guide 116. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ 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.
UN 3553 is Disilane, assigned to ERG Guide 116. This entry should be verified with shipping papers, labels and the SDS before responders commit to close-range action.
Hazard overview: Disilane is extremely flammable and pyrophoric, meaning it may ignite spontaneously in air. Moisture contact may generate hydrogen and increase fire or explosion risk.
Response guidance: Use ERG Guide 116, isolate the area, keep people upwind and avoid incompatible agents. Keep water away unless incident command confirms it is safe for the specific material.
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UN 3553 Quick Details
UN 3553
Product name: Disilane
DOT Class: 2
Placard type: Toxic Gas / Flammable Gas
ERG Guide: 116 (check current ERG)
Initial isolation: ERG 116: isolate 800m all directions initially; evacuate 1600m downwind if tank/rail car involved in fire
Common Hazards of UN 3553
- EXTREMELY FLAMMABLE.
- Will be easily ignited by heat, sparks or flames.
- Will form explosive mixtures with air. Acetylene (UN1001, UN3374) may react explosively even in the
- Disilane (UN3553) and Silane (UN2203) will ignite spontaneously in air and may re-ignite.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Vapors may travel to source of ignition and flash back.
- Cylinders exposed to fire may vent and release flammable gas through pressure relief devices.
Chemical Identity & Physical Properties
Colorless gas with a repulsive odor. Pyrophoric (ignites spontaneously in air). Heavier than air.
| Also known as | DisilaneSilicon hydrideHexahydrodisiliconSi2H6 |
| CAS Number | 1590-87-0 |
| Appearance | Colorless gas with a repulsive odor. Pyrophoric (ignites spontaneously in air). Heavier than air. |
| Flash Point | Not applicable (pyrophoric gas, ignites spontaneously) |
| Boiling Point | -14°C (7°F) |
| Vapor Density | 2.2 (heavier than air) |
| Water Reactivity | Reacts with moisture producing silica and hydrogen gas; may ignite spontaneously |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3553
Extinguishing Media
Do not use water or foam; use dry chemical or CO2 for small fires only
PPE Requirements
⚠️ Level A required; full encapsulation with SCBA; extreme fire and explosion hazard
Level A required; full encapsulation with SCBA; extreme fire and explosion hazard. Select final PPE using ERG guidance, SDS, monitoring and incident command.
Isolation & Evacuation
ERG 116: isolate 800m all directions initially; evacuate 1600m downwind if tank/rail car involved in fire
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 116).
First Actions for a UN 3553 Incident
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- Consider initial downwind evacuation for at least 800 meters (1/2 mile).
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📋 Copy & Share Field Card
UN 3553 — DisilaneHAZMAT RADIO NOTE — UN 3553
Product: Disilane
Class 2 / Toxic Gas / Flammable Gas / ERG 116
PPE: Level A required; full encapsulation with SCBA; extreme fire and explosion hazard
ISOLATION: ERG 116: isolate 800m all directions initially; evacuate 1600m downwind if tank/rail car involved in fire
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 3553 — Disilane
Class: 2 | Placard: Toxic Gas / Flammable Gas | ERG Guide: 116
Appearance: Colorless gas with a repulsive odor. Pyrophoric (ignites spontaneously in air). Heavier than air.
Water Reactivity: Reacts with moisture producing silica and hydrogen gas; may ignite spontaneously
Extinguishing: Do not use water or foam; use dry chemical or CO2 for small fires only
PPE: Level A required; full encapsulation with SCBA; extreme fire and explosion hazard
Isolation: ERG 116: isolate 800m all directions initially; evacuate 1600m downwind if tank/rail car involved in fire
— Key Hazards —
• EXTREMELY FLAMMABLE.
• Will be easily ignited by heat, sparks or flames.
• Will form explosive mixtures with air. Acetylene (UN1001, UN3374) may react explosively even in the
— First Actions —
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
• Consider initial downwind evacuation for at least 800 meters (1/2 mile).
SOURCE: allfirefighter.com/hazmat/un/disilane-un-3553 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3553 Disilane Cls2 ERG116 | ERG 116: isolate 800m all directions initially; evacuate 1600m downwind if tank/ | allfirefighter.com/hazmat/un/disilane-un-3553SMS / 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/disilane-un-3553
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Frequently Asked Questions about UN 3553
UN 3553 is Disilane, assigned to ERG Guide 116.
ERG Guide 116 applies for initial isolation, protective actions and first response guidance.
Disilane is extremely flammable and pyrophoric, meaning it may ignite spontaneously in air.
Level A required; full encapsulation with SCBA; extreme fire and explosion hazard.
ERG 116: isolate 800m all directions initially; evacuate 1600m downwind if tank/rail car involved in fire.
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.