☣️ UN 1766 • CLASS 8
Dichlorophenyltrichlorosilane
Placard: Corrosive. 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 1766
Class: 8
Placard type: Corrosive
ERG: Guide 156 (check current ERG)
Isolation: ERG 156: Isolate spill 25-50m all directions. Evacuate immediate area. Large spill: isolate 800m downwind if no fire.
Chemical & Response Details
| Also known as | Dichlorophenyl trichlorosilaneTrichlorodichlorophenylsilanePhenyl dichlorotrichlorosilaneDichlorophenyltrichlorosilane (various isomers) |
| CAS Number | 27137-85-5 |
| Appearance | Colorless to pale yellow liquid with a pungent, acrid odor. Corrosive liquid at room temperature, fumes in moist air. |
| Flash Point | Not readily ignitable but combustible; flash point data varies by isomer, generally >93C (>200F) |
| Boiling Point | Approximately 260-280C (500-536F), varies by isomer position |
| Vapor Density | Approximately 9-10 (much heavier than air) |
| Water Reactivity | Reacts violently with water, releasing toxic and corrosive HCl gas and heat. Do not use water directly on material. |
| Extinguishing | Dry chemical, CO2, or dry sand only. Do not use water or foam. Smother small fires with dry agents. |
| PPE | ⚠️ Level A or B required; full chemical-resistant suit, SCBA mandatory. Corrosive to skin, eyes, and respiratory tract. |
| Isolation | ERG 156: Isolate spill 25-50m all directions. Evacuate immediate area. Large spill: isolate 800m downwind if no fire. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Combustible material: may burn but does not ignite readily.
- Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
- When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
- Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas
- Vapors may travel to source of ignition and flash back.
- Corrosives in contact with metals may evolve flammable hydrogen gas.
- Containers may explode when heated or if contaminated with water.
- TOXIC and/or CORROSIVE; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
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.
- 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
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UN 1766 — Dichlorophenyltrichlorosilane HAZMAT RADIO NOTE — UN 1766
Product: Dichlorophenyltrichlorosilane
Class 8 / Corrosive / ERG 156
PPE: Level A or B required; full chemical-resistant suit, SCBA mandatory. Corrosive to skin, eyes, and respiratory tract.
ISOLATION: ERG 156: Isolate spill 25-50m all directions. Evacuate immediate area. Large spill: isolate 800m downwind if no 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 1766 — Dichlorophenyltrichlorosilane
Class: 8 | Placard: Corrosive | ERG Guide: 156
Appearance: Colorless to pale yellow liquid with a pungent, acrid odor. Corrosive liquid at room temperature, fumes in moist air.
Water Reactivity: Reacts violently with water, releasing toxic and corrosive HCl gas and heat. Do not use water directly on material.
Extinguishing: Dry chemical, CO2, or dry sand only. Do not use water or foam. Smother small fires with dry agents.
PPE: Level A or B required; full chemical-resistant suit, SCBA mandatory. Corrosive to skin, eyes, and respiratory tract.
Isolation: ERG 156: Isolate spill 25-50m all directions. Evacuate immediate area. Large spill: isolate 800m downwind if no fire.
— Key Hazards —
• Combustible material: may burn but does not ignite readily.
• Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
• When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
— 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.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/1766 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1766 Dichlorophenyltrichlorosilane Cls8 ERG156 | allfirefighter.com/hazmat/un/1766SMS / 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/1766
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FAQ
Combustible material: may burn but does not ignite readily. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas Vapors may travel to source of ignition and flash back. Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water. TOXIC and/or CORROSIVE; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
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 or B required; full chemical-resistant suit, SCBA mandatory. Corrosive to skin, eyes, and respiratory tract.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 156 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.