☣️ UN 3553 • CLASS 2
Disilane
Placard: Toxic Gas / Flammable Gas. 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 3553
Class: 2
Placard type: Toxic Gas / Flammable Gas
ERG: Guide 116 (check current ERG)
Isolation: ERG 116: isolate 800m all directions initially; evacuate 1600m downwind if tank/rail car involved in fire
Chemical & Response Details
| 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 |
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
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.
- Many gases are heavier than air and will spread along the ground and collect in low or confined areas
- 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
UN 3553 — Disilane HAZMAT 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 —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Many gases are heavier than air and will spread along the ground and collect in low or confined areas
SOURCE: allfirefighter.com/hazmat/un/3553 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3553 Disilane Cls2 ERG116 | ERG 116: isolate 800m all directions initially; evacuate 1600m downwind if tank/ | allfirefighter.com/hazmat/un/3553SMS / 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/3553
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FAQ
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.
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 A required; full encapsulation with SCBA; extreme fire and explosion hazard
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 116 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.