☣️ UN 1784 • CLASS 8
UN 1784 — Hexyltrichlorosilane
Placard: Corrosive. ERG Guide 156. 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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UN 1784 Quick Details
UN 1784
Product name: Hexyltrichlorosilane
DOT Class: 8
Placard type: Corrosive
ERG Guide: 156 (check current ERG)
Initial isolation: ERG 156: isolate spill 50m all directions; initial evacuation 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions
Common Hazards of UN 1784
- 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
Chemical Identity & Physical Properties
| Also known as | n-HexyltrichlorosilaneTrichloro(hexyl)silaneHexane, 1-(trichlorosilyl)-1-Hexyltrichlorosilane |
| CAS Number | 928-65-4 |
| Appearance | Colorless to pale yellow liquid with a pungent, irritating odor. Fuming liquid that releases acidic vapors upon contact with moisture. |
| Flash Point | 66C (151F) |
| Boiling Point | 195C (383F) |
| Vapor Density | 7.0 (heavier than air) |
| Water Reactivity | Reacts violently with water releasing hydrogen chloride (HCl) gas and heat. Forms corrosive hydrochloric acid solution. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1784
Extinguishing Media
Dry chemical, CO2, sand; do not use water or water-based foams
PPE Requirements
⚠️ Level B minimum; SCBA required; full face protection mandatory; chemical-resistant suit due to corrosive vapor generation
Isolation & Evacuation
ERG 156: isolate spill 50m all directions; initial evacuation 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 156).
First Actions for a UN 1784 Incident
- 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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📋 Copy & Share Field Card
UN 1784 — HexyltrichlorosilaneHAZMAT RADIO NOTE — UN 1784
Product: Hexyltrichlorosilane
Class 8 / Corrosive / ERG 156
PPE: Level B minimum; SCBA required; full face protection mandatory; chemical-resistant suit due to corrosive vapor generation
ISOLATION: ERG 156: isolate spill 50m all directions; initial evacuation 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions
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 1784 — Hexyltrichlorosilane
Class: 8 | Placard: Corrosive | ERG Guide: 156
Appearance: Colorless to pale yellow liquid with a pungent, irritating odor. Fuming liquid that releases acidic vapors upon contact with moisture.
Water Reactivity: Reacts violently with water releasing hydrogen chloride (HCl) gas and heat. Forms corrosive hydrochloric acid solution.
Extinguishing: Dry chemical, CO2, sand; do not use water or water-based foams
PPE: Level B minimum; SCBA required; full face protection mandatory; chemical-resistant suit due to corrosive vapor generation
Isolation: ERG 156: isolate spill 50m all directions; initial evacuation 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions
— 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/1784 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1784 Hexyltrichlorosilane Cls8 ERG156 | ERG 156: isolate spill 50m all directions; initial evacuation 100m in all direct | allfirefighter.com/hazmat/un/1784SMS / 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/1784
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Frequently Asked Questions about UN 1784
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 B minimum; SCBA required; full face protection mandatory; chemical-resistant suit due to corrosive vapor generation
Water reactivity: Reacts violently with water releasing hydrogen chloride (HCl) gas and heat. Forms corrosive hydrochloric acid solution.. Recommended extinguishing: Dry chemical, CO2, sand; do not use water or water-based foams.
ERG Guide 156 recommendation: ERG 156: isolate spill 50m all directions; initial evacuation 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions
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.