☣️ UN 3361 • CLASS 6
UN 3361 — Chlorosilanes, poisonous, corrosive, n.o.s.
Placard: Toxic. ERG Guide 156. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ 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.
Chlorosilanes, poisonous, corrosive, n.o.s. covers reactive chlorosilane mixtures where the exact compound must be confirmed from shipping papers or SDS.
Hazard overview: Chlorosilanes can fume in moist air and react violently with water, releasing heat, corrosive hydrogen chloride and potentially flammable gases.
Response guidance: Use ERG 156, isolate the spill area, keep personnel upwind and avoid direct water contact. Use dry agents unless product-specific data allows another method.
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UN 3361 Quick Details
UN 3361
Product name: Chlorosilanes, poisonous, corrosive, n.o.s.
DOT Class: 6
Placard type: Toxic
ERG Guide: 156 (check current ERG)
Initial isolation: ERG 156: isolate spill 25-50m all directions; evacuate 100m downwind initially; if tank/rail car involved in fire, isolate 800m all directions
Common Hazards of UN 3361
- 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; indoor, outdoor and sewer explosion hazards may exist.
- Most vapors are heavier than air; they 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 with vapors, dusts or substance may cause severe injury.
Chemical Identity & Physical Properties
Colorless to pale yellow liquids with pungent, acrid odor. Fuming in moist air. Varies by specific chlorosilane compound.
| 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. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3361
Extinguishing Media
Dry chemical, CO2, dry sand for small fires. Alcohol-resistant foam from distance for large fires. No direct water application.
PPE Requirements
⚠️ Level A or B required; SCBA mandatory; fully encapsulating suit if splash/vapor exposure risk; chemical-resistant gloves and boots
Use SCBA with Level A or B chemical protection; fully encapsulating protection is needed for splash or vapor exposure risk.
Isolation & Evacuation
ERG 156: isolate spill 25-50m all directions; evacuate 100m downwind initially; 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 3361 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.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate the spill or leak area in all directions; use the ERG guide and shipping papers to set exact distances.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials, increase downwind precautions when vapor, dust, or runoff hazards are present.
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📋 Copy & Share Field Card
UN 3361 — Chlorosilanes, poisonous, corrosive, n.oHAZMAT 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; indoor, outdoor and sewer explosion hazards may exist.
— First Actions —
• 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.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/chlorosilanes-poisonous-corrosive-n-un-3361 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3361 Chlorosilanes, poisonous, corrosive, n.o.s. Cls6 ERG156 | allfirefighter.com/hazmat/un/chlorosilanes-poisonous-corrosive-n-un-3361SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/chlorosilanes-poisonous-corrosive-n-un-3361
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Frequently Asked Questions about UN 3361
UN 3361 is a chlorosilane n.o.s. entry with toxic and corrosive hazards.
Yes. It can react violently with water or moisture and release corrosive hydrogen chloride fumes.
It may burn and can produce flammable gases when reacting with water or metals.
Dry chemical, CO2 or dry sand may be used; avoid direct water application.
SCBA and Level A or B chemical protective clothing are required depending on release severity.
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.