UN 1818 — Silicon tetrachloride
Placard: Corrosive. ERG Guide 157. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1818 is Silicon tetrachloride, a toxic corrosive fuming liquid assigned to ERG Guide 157. It reacts violently with water or moist air, producing dense hydrogen chloride fumes.
Hazard overview: UN 1818 presents water-reactive, corrosive fume, heavy vapor and acidic-runoff hazards. Do not apply water directly to product unless specialist guidance confirms a safe use.
Response guidance: For a UN 1818 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 157. Establish incident command, isolate the area, stay upwind, prevent incompatible contact, control runoff and choose entry or fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1818 should emphasize corrosive exposure routes, water or oxidizer incompatibility where applicable, air monitoring, PPE selection, decontamination and runoff containment. Use ERG 157, SDS and local SOP.
Regulatory context: Silicon tetrachloride is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by concentration, formulation, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Silicon tetrachloride should be stored in tightly closed compatible containers in a cool, dry, well-ventilated area away from water, moisture, bases, oxidizers/reducing agents where incompatible, heat and unauthorized access. Protect containers from corrosion, leakage and contamination.
UN 1818 Quick Details
Common Hazards of UN 1818
- TOXIC and CORROSIVE fuming liquid; inhalation, ingestion or contact may cause severe injury.
- Reacts violently with water or moist air, releasing heat, dense hydrogen chloride fumes and silicic acid residue.
- Vapors are heavier than air and may collect in low or confined areas.
- Liquid and fumes can burn eyes, skin and respiratory tissue.
- Non-flammable, but water reaction can be vigorous and produce dense corrosive clouds.
- Runoff may be strongly acidic and corrosive.
- Containers may rupture or fail when heated or contaminated with water.
Chemical Identity & Physical Properties
Colorless to pale yellow fuming liquid with a suffocating acrid odor. Fumes in moist air due to hydrolysis.
| Also known as | Silicon chlorideTetrachlorosilaneSilane, tetrachloro-SiCl4 |
| CAS Number | 10026-04-7 |
| Appearance | Colorless to pale yellow fuming liquid with a suffocating acrid odor. Fumes in moist air due to hydrolysis. |
| Flash Point | Not applicable (non-flammable) |
| Boiling Point | 57C (135F) |
| Vapor Density | 5.9 (much heavier than air) |
| Water Reactivity | Reacts violently with water producing heat and toxic/corrosive hydrogen chloride fumes. Do not use water directly on material. |
Fireground Response Guidance — UN 1818
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fume, dust, fire or confined-space exposure. Chemical-resistant gloves, boots, eye/face protection and protective clothing should be selected from SDS; Level A may be needed for close entry or unknown concentrations.
Isolation & Evacuation
First Actions for a UN 1818 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing vapors, fumes, dust, mist or spray and avoid skin or eye contact.
- Keep water and moisture away from released product unless incident command confirms a compatible cooling or control use.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or leak area and expand the perimeter if vapor, dust, fire involvement, water reaction or unknown concentration is present.
- Use ERG Guide 157, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1818 — Silicon tetrachlorideUse 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.