UN 3560 — Tetramethylammonium hydroxide aqueous solution with not less than 25% tetramethylammonium hydroxide
Placard: Corrosive / Toxic. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3560 is Tetramethylammonium hydroxide aqueous solution with not less than 25% tetramethylammonium hydroxide, a toxic corrosive alkaline solution assigned to ERG Guide 153. Skin contact, systemic toxicity and caustic runoff are key concerns.
Hazard overview: TOXIC and CORROSIVE tetramethylammonium hydroxide solution; skin contact can cause severe injury and systemic toxicity. Strong alkaline liquid can burn eyes, skin and respiratory tissue. Tetramethylammonium ion exposure can cause serious systemic effects; avoid all unprotected skin contact.
Response guidance: For UN 3560, isolate the spill, prevent skin contact and use SCBA with chemical splash protection. Control caustic/toxic runoff and avoid uncontrolled neutralization under ERG 153.
Firefighter training notes: Training for UN 3560 should emphasize caustic splash control, TMAH systemic toxicity, skin decontamination urgency, SCBA use and runoff containment. Use ERG 153, SDS and local SOP.
Regulatory context: Tetramethylammonium hydroxide aqueous solution with not less than 25% tetramethylammonium hydroxide is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, concentration, package type and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Tetramethylammonium hydroxide aqueous solution with not less than 25% tetramethylammonium hydroxide should be stored in compatible corrosion-resistant containers with secondary containment, restricted access and segregation from acids, oxidizers and incompatible metals/materials.
UN 3560 Quick Details
Common Hazards of UN 3560
- TOXIC and CORROSIVE tetramethylammonium hydroxide solution; skin contact can cause severe injury and systemic toxicity.
- Strong alkaline liquid can burn eyes, skin and respiratory tissue.
- Tetramethylammonium ion exposure can cause serious systemic effects; avoid all unprotected skin contact.
- Mist or aerosol can injure respiratory tissue and contaminate PPE or tools.
- Dilution or neutralization may release heat and cause splattering.
- Runoff may be caustic, toxic and harmful to waterways.
- Fire may produce nitrogen oxides, corrosive/alkaline mist and irritating toxic smoke from packaging or residues.
Chemical Identity & Physical Properties
Clear to slightly yellow viscous liquid with a strong ammonia-like odor. Typically supplied as an aqueous solution at concentrations of 25% or higher.
| Also known as | TMAHTetramethylammonium hydroxideTetrabaseN,N,N-trimethylmethanaminium hydroxideTMAOH |
| CAS Number | 75-59-2 |
| Appearance | Clear to slightly yellow viscous liquid with a strong ammonia-like odor. Typically supplied as an aqueous solution at concentrations of 25% or higher. |
| Flash Point | Not applicable (aqueous solution, concentration dependent) |
| Boiling Point | Approximately 100-130C (212-266F) depending on concentration |
| Vapor Density | Not applicable (aqueous solution) |
| Water Reactivity | No significant reaction; miscible with water, already an aqueous solution |
Fireground Response Guidance — UN 3560
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for mist, fire or confined-space exposure and chemical-resistant splash protection, gloves, boots and eye/face protection.
Isolation & Evacuation
First Actions for a UN 3560 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, gas, mist, smoke or fumes and avoid skin or eye contact.
- Avoid any unprotected skin contact and keep neutralization/dilution controlled because heat and splattering may occur.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Prevent contaminated 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 3560 — Tetramethylammonium hydroxide aqueous soUse 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.