☣️ UN 2203 • CLASS 2
Silane
Placard: Flammable Gas. 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.
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Quick details
UN 2203
Class: 2
Placard type: Flammable Gas
ERG: Guide 116 (check current ERG)
Isolation: ERG 116: Isolate spill/leak area immediately for at least 100m (330 ft) in all directions; if tank/rail car is involved in fire, isolate 800m (1/2 mile) radius; evacuate area
Chemical & Response Details
| Also known as | Silicon tetrahydrideMonosilaneSilicon hydrideSiH4 |
| CAS Number | 7803-62-5 |
| Appearance | Colorless gas with a repulsive, garlic-like or rotten fish odor. Pyrophoric — ignites spontaneously in air at room temperature above approximately 21°C (70°F). |
| Flash Point | Not applicable (pyrophoric gas, ignites spontaneously in air) |
| Boiling Point | -112°C (-170°F) |
| Vapor Density | 1.1 (slightly heavier than air) |
| Water Reactivity | Reacts with water to produce hydrogen gas and silicon dioxide; reaction accelerates with heat |
| Extinguishing | Do not use water or foam; use dry chemical, CO2, or sand for small fires; evacuate area for large fires |
| PPE | ⚠️ Level A required due to pyrophoric nature and extreme flammability; SCBA mandatory; fire-resistant clothing; remote operations preferred |
| Isolation | ERG 116: Isolate spill/leak area immediately for at least 100m (330 ft) in all directions; if tank/rail car is involved in fire, isolate 800m (1/2 mile) radius; evacuate area |
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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UN 2203 — Silane HAZMAT RADIO NOTE — UN 2203
Product: Silane
Class 2 / Flammable Gas / ERG 116
PPE: Level A required due to pyrophoric nature and extreme flammability; SCBA mandatory; fire-resistant clothing; remote operations preferred
ISOLATION: ERG 116: Isolate spill/leak area immediately for at least 100m (330 ft) in all directions; if tank/rail car is involved in fire, isolate 800m (1/2 mile) radius; evacuate area
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 2203 — Silane
Class: 2 | Placard: Flammable Gas | ERG Guide: 116
Appearance: Colorless gas with a repulsive, garlic-like or rotten fish odor. Pyrophoric — ignites spontaneously in air at room temperature above approximately 21°C (70°F).
Water Reactivity: Reacts with water to produce hydrogen gas and silicon dioxide; reaction accelerates with heat
Extinguishing: Do not use water or foam; use dry chemical, CO2, or sand for small fires; evacuate area for large fires
PPE: Level A required due to pyrophoric nature and extreme flammability; SCBA mandatory; fire-resistant clothing; remote operations preferred
Isolation: ERG 116: Isolate spill/leak area immediately for at least 100m (330 ft) in all directions; if tank/rail car is involved in fire, isolate 800m (1/2 mile) radius; evacuate area
— 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/2203 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2203 Silane Cls2 ERG116 | ERG 116: Isolate spill/leak area immediately for at least 100m (330 ft) in all d | allfirefighter.com/hazmat/un/2203SMS / 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/2203
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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 due to pyrophoric nature and extreme flammability; SCBA mandatory; fire-resistant clothing; remote operations preferred
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.