UN 3394 — Organometallic substance, liquid, pyrophoric, waterreactive
Placard: Spontaneously Combustible. ERG Guide 135. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3394 is Organometallic substance, liquid, pyrophoric, waterreactive, a broad organometallic entry assigned to ERG Guide 135. The main concern is pyrophoric and water-reactive ignition; exact compound/SDS verification is critical.
Hazard overview: PYROPHORIC and WATER-REACTIVE organometallic liquid; may ignite spontaneously in air or moist air. Water contact can release flammable gases, heat and violent splattering or ignition. May burn rapidly and re-ignite after apparent extinguishment.
Response guidance: For UN 3394, isolate the area, keep all water/moisture away and use SCBA from a protected position. Use compatible dry media only and watch for re-ignition under ERG 135.
Firefighter training notes: Training for UN 3394 should emphasize pyrophoric/water-reactive behavior, dry-media tactics, re-ignition checks, moisture exclusion, SCBA use and runoff/debris control. Use ERG 135, SDS and local SOP.
Regulatory context: Organometallic substance, liquid, pyrophoric, waterreactive is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, concentration, formulation and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Organometallic substance, liquid, pyrophoric, waterreactive should be stored dry in compatible sealed containers under inert gas or approved protective liquid where required, away from water, moisture, air, heat, ignition sources and oxidizers.
UN 3394 Quick Details
Common Hazards of UN 3394
- PYROPHORIC and WATER-REACTIVE organometallic liquid; may ignite spontaneously in air or moist air.
- Water contact can release flammable gases, heat and violent splattering or ignition.
- May burn rapidly and re-ignite after apparent extinguishment.
- Some compounds are transported under inert gas or hydrocarbon solvent; package damage can change fire behavior.
- Water, foam, CO2 and halogenated agents can worsen the reaction or spread burning material.
- Fire may produce toxic metal oxide fumes, carbon monoxide and irritating organic smoke.
- Exact metal, ligand, solvent and water-reactivity severity must be verified from SDS.
Chemical Identity & Physical Properties
Typically colorless to pale yellow liquid with pungent or distinctive odor. Highly reactive, spontaneously ignites in air and reacts violently with water. Often used as specialized chemical reagents.
| Also known as | Pyrophoric organometallic liquidWater-reactive organometallic compoundOrganometallic reagentMetal alkyl compound |
| Appearance | Typically colorless to pale yellow liquid with pungent or distinctive odor. Highly reactive, spontaneously ignites in air and reacts violently with water. Often used as specialized chemical reagents. |
| Flash Point | Not applicable (pyrophoric, spontaneously ignites) |
| Boiling Point | Varies by specific compound (typically 50-150C range) |
| Vapor Density | Greater than 1 (heavier than air) |
| Water Reactivity | Reacts violently with water, generates flammable gases and heat. Do not use water. |
Fireground Response Guidance — UN 3394
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA with fire/chemical protection and distance from reactive material. Level A or B may be needed for unknown compound, vapor, splash or residue contact.
Isolation & Evacuation
First Actions for a UN 3394 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.
- Exclude water, moisture, foam and incompatible extinguishing media.
- Avoid disturbing residue because pyrophoric or water-reactive material may re-ignite.
- 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 135, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3394 — Organometallic substance, liquid, pyrophUse 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.