UN 1183 — Ethyldichlorosilane
Placard: Dangerous When Wet. ERG Guide 139. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Ethyldichlorosilane is a substance that produces flammable and toxic gases on contact with water. It is a colorless to pale yellow liquid with a sharp, pungent, irritating odor that fumes in moist air due to reaction with atmospheric moisture.
Hazard overview: Ethyldichlorosilane may ignite on contact with water or moist air, producing flammable and toxic gases. It reacts violently with water, producing flammable hydrogen gas and corrosive hydrochloric acid fumes.
Response guidance: In case of a spill, isolate the area immediately and use dry chemical, CO2, dry sand, or dry earth for extinguishing. Wear a Level B minimum with SCBA required, and a full chemical-resistant suit if contact is likely.
UN 1183 Quick Details
Common Hazards of UN 1183
- Produce flammable and toxic 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.
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
Chemical Identity & Physical Properties
Ethyldichlorosilane is a colorless to pale yellow liquid with a sharp, pungent, irritating odor that fumes in moist air due to reaction with atmospheric moisture.
| Also known as | DichloroethylsilaneEthylsilicon dichlorideSilane, dichloroethyl-EDCS |
| CAS Number | 1789-58-8 |
| Appearance | Colorless to pale yellow liquid with a sharp, pungent, irritating odor. Fuming in moist air due to reaction with atmospheric moisture. |
| Flash Point | -28C (-18F) |
| Boiling Point | 75-76C (167-169F) |
| Vapor Density | 4.5 (heavier than air) |
| Water Reactivity | Reacts violently with water producing flammable hydrogen gas and corrosive hydrochloric acid fumes. May ignite spontaneously. |
Fireground Response Guidance — UN 1183
Extinguishing Media
PPE Requirements
Wear a Level B minimum with SCBA required, and a full chemical-resistant suit if contact is likely, as ethyldichlorosilane reacts violently with water and produces flammable and toxic gases.
Isolation & Evacuation
First Actions for a UN 1183 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
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
📋 Copy & Share Field Card
UN 1183 — EthyldichlorosilaneUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.