UN 3281 — Metal carbonyls, liquid, n.o.s.
Placard: Toxic. ERG Guide 151. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3281 is Metal carbonyls, liquid, n.o.s., a broad extremely toxic metal carbonyl liquid entry assigned to ERG Guide 151. Volatile vapor and CO/metal fume hazards matter.
Hazard overview: EXTREMELY TOXIC volatile metal carbonyl liquid, n.o.s.; inhalation may be fatal. Many metal carbonyls can be absorbed through skin and may have delayed severe effects. Some are flammable or decompose readily when heated, releasing carbon monoxide and metal fumes.
Response guidance: For UN 3281, isolate the area, avoid all skin contact and use SCBA with chemical protection. Prevent runoff spread and verify exact compound with SDS and ERG 151.
Firefighter training notes: Training for UN 3281 should emphasize high-toxicity exposure routes, skin absorption, SCBA/Level A decisions, decontamination, runoff control and exact-compound verification. Use ERG 151, SDS and local SOP.
Regulatory context: Metal carbonyls, liquid, n.o.s. is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, composition, concentration and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Metal carbonyls, liquid, n.o.s. should be stored in tightly closed compatible containers away from moisture, heat, ignition sources and incompatible acids/bases/oxidizers as specified by SDS.
UN 3281 Quick Details
Common Hazards of UN 3281
- EXTREMELY TOXIC volatile metal carbonyl liquid, n.o.s.; inhalation may be fatal.
- Many metal carbonyls can be absorbed through skin and may have delayed severe effects.
- Some are flammable or decompose readily when heated, releasing carbon monoxide and metal fumes.
- Vapors are heavier than air and may collect in low or confined areas.
- Water or heat may decompose some carbonyls and increase toxic gas release.
- Fire may produce metal oxide fumes, carbon monoxide and toxic smoke.
- Exact metal carbonyl must be verified before media selection or entry.
Chemical Identity & Physical Properties
Colorless to pale yellow liquids with characteristic odors. Most metal carbonyls are volatile liquids at room temperature, though appearance varies depending on the specific metal.
| Also known as | Metal carbonyl compoundsCarbonyl metal complexesTransition metal carbonylsOrganometallic carbonyls |
| Appearance | Colorless to pale yellow liquids with characteristic odors. Most metal carbonyls are volatile liquids at room temperature, though appearance varies depending on the specific metal. |
| Flash Point | Varies by specific compound; many are flammable with flash points below 23C (73F) |
| Boiling Point | Varies by compound; typically range from 43C to 230C (109F to 446F) |
| Vapor Density | Heavier than air for most metal carbonyls (typically 3-7 times air density) |
| Water Reactivity | May decompose in water, releasing toxic carbon monoxide gas; avoid water contact when possible |
Fireground Response Guidance — UN 3281
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and full chemical protective clothing. Level A may be needed for unknown concentration, heavy vapor, splash or high skin-absorption risk.
Isolation & Evacuation
First Actions for a UN 3281 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 until the exact product compatibility is verified.
- 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 151, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3281 — Metal carbonyls, liquid, n.o.s.Use 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.