☣️ UN 3361 • CLASS 6
Chlorosilanes, poisonous, corrosive, n.o.s.
Placard: Toxic. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ 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 3361
Class: 6
Placard type: Toxic
ERG: Guide 156 (check current ERG)
Isolation: ERG 156: isolate spill 25-50m all directions; evacuate 100m downwind initially; if tank/rail car involved in fire, isolate 800m all directions
Chemical & Response Details
| Also known as | ChlorosilanesOrganosilicon chloridesSilicon chloride compoundsReactive chlorosilanes |
| Appearance | Colorless to pale yellow liquids with pungent, acrid odor. Fuming in moist air. Varies by specific chlorosilane compound. |
| Flash Point | Varies by compound, typically -28C to 16C (-18F to 61F) — combustible to flammable |
| Boiling Point | Varies by compound, typically 30C to 120C (86F to 248F) |
| Vapor Density | 3-5 (heavier than air, varies by compound) |
| Water Reactivity | Reacts violently with water releasing HCl gas (corrosive), hydrogen gas (flammable), and heat. Do not use water directly on material. |
| Extinguishing | Dry chemical, CO2, dry sand for small fires. Alcohol-resistant foam from distance for large fires. No direct water application. |
| PPE | ⚠️ Level A or B required; SCBA mandatory; fully encapsulating suit if splash/vapor exposure risk; chemical-resistant gloves and boots |
| Isolation | ERG 156: isolate spill 25-50m all directions; evacuate 100m downwind initially; if tank/rail car involved in fire, isolate 800m all directions |
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 3361 — Chlorosilanes, poisonous, corrosive, n.o HAZMAT RADIO NOTE — UN 3361
Product: Chlorosilanes, poisonous, corrosive, n.o.s.
Class 6 / Toxic / ERG 156
PPE: Level A or B required; SCBA mandatory; fully encapsulating suit if splash/vapor exposure risk; chemical-resistant gloves and boots
ISOLATION: ERG 156: isolate spill 25-50m all directions; evacuate 100m downwind initially; 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 3361 — Chlorosilanes, poisonous, corrosive, n.o.s.
Class: 6 | Placard: Toxic | ERG Guide: 156
Appearance: Colorless to pale yellow liquids with pungent, acrid odor. Fuming in moist air. Varies by specific chlorosilane compound.
Water Reactivity: Reacts violently with water releasing HCl gas (corrosive), hydrogen gas (flammable), and heat. Do not use water directly on material.
Extinguishing: Dry chemical, CO2, dry sand for small fires. Alcohol-resistant foam from distance for large fires. No direct water application.
PPE: Level A or B required; SCBA mandatory; fully encapsulating suit if splash/vapor exposure risk; chemical-resistant gloves and boots
Isolation: ERG 156: isolate spill 25-50m all directions; evacuate 100m downwind initially; 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/3361 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3361 Chlorosilanes, poisonous, corrosive, n.o.s. Cls6 ERG156 | allfirefighter.com/hazmat/un/3361SMS / 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/3361
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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; SCBA mandatory; fully encapsulating suit if splash/vapor exposure risk; chemical-resistant gloves and boots
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.