UN 2826 — Ethyl chlorothioformate
Placard: Corrosive. ERG Guide 155. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2826 At a Glance
UN 2826 (Ethyl chlorothioformate) is listed as DOT Class 8 Corrosive and is assigned to ERG Guide 155. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
UN 2826 is Ethyl chlorothioformate, a flammable toxic corrosive chlorothioformate assigned to ERG Guide 155. Water reaction and flashback are key hazards.
Hazard overview: HIGHLY FLAMMABLE, TOXIC and CORROSIVE chlorothioformate liquid; vapors may ignite easily. Reacts with water or moist air, releasing hydrogen chloride and sulfur-containing toxic/corrosive gases. Vapors are heavier than air and may travel to ignition sources and flash back.
Response guidance: For UN 2826, isolate the spill, stay upwind and use SCBA with chemical protection. Control moisture contact, use compatible dry agents and contain acidic/toxic runoff under ERG 155.
Firefighter training notes: Training for UN 2826 should emphasize moisture-reactive corrosive fuming, dry-agent choice, SCBA/Level A decisions, decontamination and acidic runoff control. Use ERG 155, SDS and local SOP.
Regulatory context: Ethyl chlorothioformate 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: Ethyl chlorothioformate should be stored dry in tightly closed compatible containers away from water, moisture, bases, alcohols/amines where incompatible, heat and unauthorized access.
UN 2826 Quick Details
Common Hazards of UN 2826
- HIGHLY FLAMMABLE, TOXIC and CORROSIVE chlorothioformate liquid; vapors may ignite easily.
- Reacts with water or moist air, releasing hydrogen chloride and sulfur-containing toxic/corrosive gases.
- Vapors are heavier than air and may travel to ignition sources and flash back.
- Liquid and vapor can burn eyes, skin and respiratory tissue.
- Fire may produce hydrogen chloride, sulfur oxides, phosgene-type gases and other toxic smoke.
- Runoff may be acidic, toxic and flammable-contaminated.
- Containers may rupture or explode when heated or contaminated with water.
Chemical Identity & Physical Properties
Colorless to pale yellow liquid with a pungent, irritating odor. Liquid at room temperature.
| Also known as | Ethyl chlorothionoformateChlorothioformic acid ethyl esterEthoxycarbonothioyl chlorideEthyl chlorocarbonothioate |
| CAS Number | 2941-64-2 |
| Appearance | Colorless to pale yellow liquid with a pungent, irritating odor. Liquid at room temperature. |
| Flash Point | -7C (19F) |
| Boiling Point | 137-139C (279-282F) |
| Vapor Density | 3.3 (heavier than air) |
| Water Reactivity | Reacts with water and moisture, releasing HCl and toxic gases; avoid water contact |
Fireground Response Guidance — UN 2826
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical-resistant protective clothing. Level A may be needed for heavy vapor, splash, fuming or unknown concentrations.
Isolation & Evacuation
First Actions for a UN 2826 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind, uphill and upstream.
- Eliminate ignition sources if this can be done safely.
- Keep water or moisture contact controlled because reaction or re-ignition hazards may be severe.
- Avoid breathing vapor, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Prevent contaminated liquid, dust, runoff and decontamination waste from spreading.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 155, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2826 — Ethyl chlorothioformateUse 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.