☣️ UN 2534 • CLASS 2
UN 2534 — Methylchlorosilane
Placard: Toxic Gas. ERG Guide 119. 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 2534 Quick Details
UN 2534
Product name: Methylchlorosilane
DOT Class: 2
Placard type: Toxic Gas
ERG Guide: 119 (check current ERG)
Initial isolation: ERG 119: Isolate spill area immediate 100m in all directions. For large spill, isolate 500m all directions. Evacuate area 800m downwind if fire involves containers.
Common Hazards of UN 2534
- TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and
- Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
- Fire will produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may cause environmental contamination.
- Flammable; may be ignited by heat, sparks or flames.
- May form explosive mixtures with air. Ethylene oxide (UN1040) may react explosively even in the
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
Chemical Identity & Physical Properties
| Also known as | MethylchlorosilaneChloromethylsilaneSilane, chloromethyl-Methylsilyl chloride |
| CAS Number | 993-00-0 |
| Appearance | Colorless gas or fuming liquid with a pungent, irritating odor. Highly reactive with moisture in air, producing white fumes of hydrogen chloride. |
| Flash Point | -20C (-4F) |
| Boiling Point | 8C (46F) |
| Vapor Density | 2.9 (heavier than air) |
| Water Reactivity | Reacts violently with water, releasing toxic and corrosive hydrogen chloride gas 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 2534
Extinguishing Media
Dry chemical, CO2, dry sand. Do not use water or foam directly on material. Use water spray to cool containers from distance.
PPE Requirements
⚠️ Level A minimum for spill response. Full encapsulating chemical protective suit with SCBA required. Material is highly toxic by inhalation and skin contact.
Isolation & Evacuation
ERG 119: Isolate spill area immediate 100m in all directions. For large spill, isolate 500m all directions. Evacuate area 800m downwind if fire involves containers.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 119).
First Actions for a UN 2534 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.
- Many gases are heavier than air and will spread along the ground and collect in low or confined areas
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- 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 2534 — MethylchlorosilaneHAZMAT RADIO NOTE — UN 2534
Product: Methylchlorosilane
Class 2 / Toxic Gas / ERG 119
PPE: Level A minimum for spill response. Full encapsulating chemical protective suit with SCBA required. Material is highly toxic by inhalation and skin contact.
ISOLATION: ERG 119: Isolate spill area immediate 100m in all directions. For large spill, isolate 500m all directions. Evacuate area 800m downwind if fire involves containers.
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 2534 — Methylchlorosilane
Class: 2 | Placard: Toxic Gas | ERG Guide: 119
Appearance: Colorless gas or fuming liquid with a pungent, irritating odor. Highly reactive with moisture in air, producing white fumes of hydrogen chloride.
Water Reactivity: Reacts violently with water, releasing toxic and corrosive hydrogen chloride gas and heat. Do not use water directly on material.
Extinguishing: Dry chemical, CO2, dry sand. Do not use water or foam directly on material. Use water spray to cool containers from distance.
PPE: Level A minimum for spill response. Full encapsulating chemical protective suit with SCBA required. Material is highly toxic by inhalation and skin contact.
Isolation: ERG 119: Isolate spill area immediate 100m in all directions. For large spill, isolate 500m all directions. Evacuate area 800m downwind if fire involves containers.
— Key Hazards —
• TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and
• Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
• Fire will produce irritating, corrosive and/or toxic gases.
— 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.
• Many gases are heavier than air and will spread along the ground and collect in low or confined areas
SOURCE: allfirefighter.com/hazmat/un/2534 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2534 Methylchlorosilane Cls2 ERG119 | ERG 119: Isolate spill area immediate 100m in all directions. For large spill, i | allfirefighter.com/hazmat/un/2534SMS / 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/2534
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Frequently Asked Questions about UN 2534
TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may cause environmental contamination. Flammable; may be ignited by heat, sparks or flames. May form explosive mixtures with air. Ethylene oxide (UN1040) may react explosively even in the Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Vapors from liquefied gas are initially heavier than air and spread along ground.
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 minimum for spill response. Full encapsulating chemical protective suit with SCBA required. Material is highly toxic by inhalation and skin contact.
Water reactivity: Reacts violently with water, releasing toxic and corrosive hydrogen chloride gas and heat. Do not use water directly on material.. Recommended extinguishing: Dry chemical, CO2, dry sand. Do not use water or foam directly on material. Use water spray to cool containers from distance..
ERG Guide 119 recommendation: ERG 119: Isolate spill area immediate 100m in all directions. For large spill, isolate 500m all directions. Evacuate area 800m downwind if fire involves containers.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 119 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.