☣️ UN 2986 • CLASS 8
UN 2986 — Chlorosilanes, corrosive, flammable, n.o.s.
Placard: Corrosive. ERG Guide 155. 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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UN 2986 Quick Details
UN 2986
Product name: Chlorosilanes, corrosive, flammable, n.o.s.
DOT Class: 8
Placard type: Corrosive
ERG Guide: 155 (check current ERG)
Initial isolation: ERG 155: Initial isolation 100m (330 ft) all directions. Spill: evacuate 800m (0.5 mi) downwind daytime, 2.5 km (1.5 mi) nighttime. Fire: evacuate 1600m (1 mi) radius.
Common Hazards of UN 2986
- HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
- Vapors form explosive mixtures with air: indoors, outdoors and sewers explosion hazards.
- 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.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff.
- Corrosives in contact with metals may evolve flammable hydrogen gas.
- Containers may explode when heated or if contaminated with water.
Chemical Identity & Physical Properties
| Also known as | Chlorosilanes n.o.s.Corrosive chlorosilane compoundsFlammable organosilicon chloridesSilicon chloride derivatives |
| Appearance | Typically colorless to pale yellow liquids with a pungent, acrid, irritating odor. Most chlorosilanes are fuming liquids that react with atmospheric moisture to produce hydrochloric acid vapors. |
| Flash Point | -18°C to 10°C (0°F to 50°F) depending on specific compound - highly flammable |
| Boiling Point | 30°C to 120°C (86°F to 248°F) depending on specific chlorosilane compound |
| Vapor Density | 3.5 to 7.5 (significantly heavier than air) - vapors accumulate in low areas |
| Water Reactivity | Reacts violently with water, releasing heat and highly corrosive hydrochloric acid fumes and flammable hydrogen gas. 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 2986
Extinguishing Media
Dry chemical, carbon dioxide, or dry sand only. Do NOT use water, foam, or halogenated extinguishing agents due to violent water reactivity.
PPE Requirements
⚠️ Level A required for significant releases. Butyl rubber or Viton gloves and suit materials. Full-face SCBA mandatory. Standard turnout gear provides NO protection against corrosive vapors.
Isolation & Evacuation
ERG 155: Initial isolation 100m (330 ft) all directions. Spill: evacuate 800m (0.5 mi) downwind daytime, 2.5 km (1.5 mi) nighttime. Fire: evacuate 1600m (1 mi) radius.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 155).
First Actions for a UN 2986 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 2986 — Chlorosilanes, corrosive, flammable, n.oHAZMAT RADIO NOTE — UN 2986
Product: Chlorosilanes, corrosive, flammable, n.o.s.
Class 8 / Corrosive / ERG 155
PPE: Level A required for significant releases. Butyl rubber or Viton gloves and suit materials. Full-face SCBA mandatory. Standard turnout gear provides NO protection against corrosive vapors.
ISOLATION: ERG 155: Initial isolation 100m (330 ft) all directions. Spill: evacuate 800m (0.5 mi) downwind daytime, 2.5 km (1.5 mi) nighttime. Fire: evacuate 1600m (1 mi) radius.
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 2986 — Chlorosilanes, corrosive, flammable, n.o.s.
Class: 8 | Placard: Corrosive | ERG Guide: 155
Appearance: Typically colorless to pale yellow liquids with a pungent, acrid, irritating odor. Most chlorosilanes are fuming liquids that react with atmospheric moisture to produce hydrochloric acid vapors.
Water Reactivity: Reacts violently with water, releasing heat and highly corrosive hydrochloric acid fumes and flammable hydrogen gas. Do not use water directly on material.
Extinguishing: Dry chemical, carbon dioxide, or dry sand only. Do NOT use water, foam, or halogenated extinguishing agents due to violent water reactivity.
PPE: Level A required for significant releases. Butyl rubber or Viton gloves and suit materials. Full-face SCBA mandatory. Standard turnout gear provides NO protection against corrosive vapors.
Isolation: ERG 155: Initial isolation 100m (330 ft) all directions. Spill: evacuate 800m (0.5 mi) downwind daytime, 2.5 km (1.5 mi) nighttime. Fire: evacuate 1600m (1 mi) radius.
— Key Hazards —
• HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
• Vapors form explosive mixtures with air: indoors, outdoors and sewers explosion hazards.
• Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas
— 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/2986 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2986 Chlorosilanes, corrosive, flammable, n.o.s. Cls8 ERG155 | allfirefighter.com/hazmat/un/2986SMS / 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/2986
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Frequently Asked Questions about UN 2986
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. 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. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.
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 required for significant releases. Butyl rubber or Viton gloves and suit materials. Full-face SCBA mandatory. Standard turnout gear provides NO protection against corrosive vapors.
Water reactivity: Reacts violently with water, releasing heat and highly corrosive hydrochloric acid fumes and flammable hydrogen gas. Do not use water directly on material.. Recommended extinguishing: Dry chemical, carbon dioxide, or dry sand only. Do NOT use water, foam, or halogenated extinguishing agents due to violent water reactivity..
ERG Guide 155 recommendation: ERG 155: Initial isolation 100m (330 ft) all directions. Spill: evacuate 800m (0.5 mi) downwind daytime, 2.5 km (1.5 mi) nighttime. Fire: evacuate 1600m (1 mi) radius.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 155 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.