UN 2534 — Methylchlorosilane
Placard: Toxic Gas. ERG Guide 119. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2534 is Methylchlorosilane, a flammable corrosive liquefied gas assigned to ERG Guide 119. Moisture can release HCl fumes and heat.
Hazard overview: FLAMMABLE and CORROSIVE liquefied gas; may ignite easily and form explosive mixtures with air. Reacts with water or moist air, releasing hydrogen chloride fumes and heat. Gas or liquefied gas contact can cause chemical burns and frostbite.
Response guidance: For UN 2534, isolate the spill or leak, stay upwind and use SCBA with chemical protection. Control moisture contact, contain acidic runoff and use compatible dry media or protected cylinder cooling under ERG 119.
Firefighter training notes: Training for UN 2534 should emphasize water-reactive corrosive fuming, dry-agent selection, SCBA/Level A decisions, decontamination and acidic runoff control. Use ERG 119, SDS and local SOP.
Regulatory context: Methylchlorosilane is regulated as a hazardous material for transport and emergency response. Storage, exposure, spill reporting, waste and fire-code duties depend on quantity, concentration and jurisdiction; verify shipping papers, SDS and local authority requirements.
Storage & handling: Methylchlorosilane cylinders should be secured in a cool, ventilated gas-storage area away from heat, physical damage and incompatible materials. Provide leak detection, ventilation and emergency planning according to SDS and local code.
UN 2534 Quick Details
Common Hazards of UN 2534
- FLAMMABLE and CORROSIVE liquefied gas; may ignite easily and form explosive mixtures with air.
- Reacts with water or moist air, releasing hydrogen chloride fumes and heat.
- Gas or liquefied gas contact can cause chemical burns and frostbite.
- Vapors from liquefied gas may spread along the ground and flash back.
- Cylinders exposed to fire may vent, rupture or rocket.
- Fire may produce hydrogen chloride, silicon oxides and other toxic/corrosive gases.
- Do not extinguish a leaking gas fire unless the gas flow can be stopped safely.
Chemical Identity & Physical Properties
Colorless gas or fuming liquid with a pungent, irritating odor. Highly reactive with moisture in air, producing white fumes of hydrogen chloride.
| 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. |
Fireground Response Guidance — UN 2534
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical-resistant protective clothing. Level A may be needed for heavy fuming, splash risk, liquefied gas contact or unknown concentrations.
Isolation & Evacuation
First Actions for a UN 2534 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind and keep people out of low or poorly ventilated areas.
- Eliminate ignition sources if safe and do not extinguish a leaking gas fire unless flow can be stopped.
- Do not touch leaking cylinders or liquefied gas without proper training and PPE.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 119, SDS, cylinder markings and air monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2534 — MethylchlorosilaneUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.