UN 3278 — Organophosphorus compound, liquid, poisonous, n.o.s.
Placard: Toxic. ERG Guide 151. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3278 is Organophosphorus compound, liquid, poisonous, n.o.s., a broad toxic organophosphorus liquid entry assigned to ERG Guide 151. Skin absorption and exact compound verification are critical.
Hazard overview: HIGHLY TOXIC organophosphorus liquid, n.o.s.; inhalation, ingestion or skin absorption may be fatal. Skin contact and contaminated clothing are major exposure concerns. Cholinesterase-inhibiting behavior is possible for some organophosphorus compounds; verify exact identity.
Response guidance: For UN 3278, 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 3278 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: Organophosphorus compound, liquid, poisonous, 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: Organophosphorus compound, liquid, poisonous, n.o.s. should be stored in tightly closed compatible containers with ventilation, secondary containment, restricted access and SDS-based segregation from incompatible materials.
UN 3278 Quick Details
Common Hazards of UN 3278
- HIGHLY TOXIC organophosphorus liquid, n.o.s.; inhalation, ingestion or skin absorption may be fatal.
- Skin contact and contaminated clothing are major exposure concerns.
- Cholinesterase-inhibiting behavior is possible for some organophosphorus compounds; verify exact identity.
- Combustibility varies; fire may produce phosphorus oxides, nitrogen/sulfur oxides and toxic smoke.
- Some compounds hydrolyze slowly in water or react with strong acids/bases.
- Runoff may carry persistent toxic organophosphorus contamination.
- Exact active compound, concentration and solvent must be verified from SDS.
Chemical Identity & Physical Properties
Variable appearance depending on specific compound; typically colorless to amber liquid with mild to strong odor. Most are oily liquids at room temperature.
| Also known as | Organophosphate liquidPhosphorus-based pesticide liquidOP compound liquidOrganophosphorus poison liquid |
| Appearance | Variable appearance depending on specific compound; typically colorless to amber liquid with mild to strong odor. Most are oily liquids at room temperature. |
| Flash Point | Variable, typically 25-93C (77-200F) depending on specific compound |
| Boiling Point | Variable, typically 100-300C (212-572F) depending on specific compound |
| Vapor Density | Variable, typically 3-10 (heavier than air) depending on specific compound |
| Water Reactivity | Most compounds have low water reactivity; some may hydrolyze slowly in water |
Fireground Response Guidance — UN 3278
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 3278 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.
- 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 3278 — Organophosphorus compound, liquid, poisoUse 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.