UN 2651 — Diaminodiphenylmethane
Placard: Toxic. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2651 is Diaminodiphenylmethane, a toxic aromatic amine entry assigned to ERG Guide 153. Skin absorption and exact form/isomer review are important.
Hazard overview: TOXIC aromatic amine material; inhalation, ingestion or skin absorption may cause serious injury. Skin contact and contaminated clothing are major exposure concerns. Combustible solid/liquid: may burn but does not ignite readily.
Response guidance: For UN 2651, isolate the area, avoid skin contact and use SCBA where dust, vapor, mist or fire is present. Prevent spread of contaminated runoff, cool containers from protection and verify controls with SDS and ERG 153.
Firefighter training notes: Training for UN 2651 should emphasize toxic exposure routes, skin absorption, SCBA use, dust/vapor control, decontamination, runoff containment and SDS verification. Use ERG 153, SDS and local SOP.
Regulatory context: Diaminodiphenylmethane 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: Diaminodiphenylmethane should be stored in tightly closed compatible containers with ventilation, secondary containment, restricted access and SDS-based segregation from incompatible materials.
UN 2651 Quick Details
Common Hazards of UN 2651
- TOXIC aromatic amine material; inhalation, ingestion or skin absorption may cause serious injury.
- Skin contact and contaminated clothing are major exposure concerns.
- Combustible solid/liquid: may burn but does not ignite readily.
- Heating or fire may produce nitrogen oxides and toxic aromatic amine smoke.
- Molten material, if present, can cause thermal and toxic contact exposure.
- Runoff may carry toxic amine contamination.
- Exact isomer/form and physical state should be verified from SDS.
Chemical Identity & Physical Properties
Tan to brown crystalline solid or flakes at room temperature. Faint amine-like odor. May be shipped as a molten liquid.
| Also known as | 4,4'-MethylenedianilineMDABis(4-aminophenyl)methaneDiaminodiphenylmethane4,4'-Diaminodiphenyl methane |
| CAS Number | 101-77-9 |
| Appearance | Tan to brown crystalline solid or flakes at room temperature. Faint amine-like odor. May be shipped as a molten liquid. |
| Flash Point | 220°C (428°F) |
| Boiling Point | 398-399°C (748-750°F) |
| Vapor Density | 6.8 (heavier than air) |
| Water Reactivity | No significant reaction with water; slightly soluble |
Fireground Response Guidance — UN 2651
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for dust, vapor, mist, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing.
Isolation & Evacuation
First Actions for a UN 2651 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 dust, liquid, runoff and decontamination waste from spreading.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 153, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2651 — DiaminodiphenylmethaneUse 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.