UN 2845 — Ethyl phosphonous dichloride, anhydrous
Placard: Toxic. ERG Guide 135. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2845 is Ethyl phosphonous dichloride, anhydrous, a toxic corrosive anhydrous phosphorus chloride assigned to ERG Guide 135. Moisture releases HCl and heat.
Hazard overview: TOXIC, CORROSIVE and water-reactive organophosphorus chloride; inhalation or contact can cause severe injury. Reacts with water or moist air, releasing hydrogen chloride, heat and acidic phosphorus-containing products. May be flammable or combustible depending on conditions; keep ignition sources away.
Response guidance: For UN 2845, 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 135.
Firefighter training notes: Training for UN 2845 should emphasize moisture-reactive corrosive fuming, dry-agent choice, SCBA/Level A decisions, decontamination and acidic runoff control. Use ERG 135, SDS and local SOP.
Regulatory context: Ethyl phosphonous dichloride, anhydrous 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 phosphonous dichloride, anhydrous should be stored dry in tightly closed compatible containers away from water, moisture, bases, alcohols/amines where incompatible, heat and unauthorized access.
UN 2845 Quick Details
Common Hazards of UN 2845
- TOXIC, CORROSIVE and water-reactive organophosphorus chloride; inhalation or contact can cause severe injury.
- Reacts with water or moist air, releasing hydrogen chloride, heat and acidic phosphorus-containing products.
- May be flammable or combustible depending on conditions; keep ignition sources away.
- Fumes are corrosive and can collect in poorly ventilated or low areas.
- Fire may produce hydrogen chloride, phosphorus oxides and other toxic/corrosive gases.
- Runoff may be acidic, toxic and corrosive.
- Containers may rupture when heated or contaminated with water.
Chemical Identity & Physical Properties
Colorless to pale yellow fuming liquid with a pungent, irritating odor. Fumes in moist air due to hydrolysis reaction.
| Also known as | Ethylphosphonous dichlorideEthyl dichlorophosphineDichloroethylphosphineEthylphosphorous dichloride |
| CAS Number | 1498-51-7 |
| Appearance | Colorless to pale yellow fuming liquid with a pungent, irritating odor. Fumes in moist air due to hydrolysis reaction. |
| Flash Point | Not applicable (pyrophoric/water-reactive) |
| Boiling Point | 58-60C (136-140F) |
| Vapor Density | 4.1 (heavier than air) |
| Water Reactivity | Reacts violently with water producing toxic and flammable phosphine gas and hydrochloric acid. Do not use water except as fog for cooling. |
Fireground Response Guidance — UN 2845
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 2845 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.
- Avoid breathing vapor, dust, mist, smoke or fumes and avoid skin or eye contact.
- Keep water or moisture contact controlled because reaction or re-ignition hazards may be severe.
- 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 135, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2845 — Ethyl phosphonous dichloride, anhydrousUse 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.