UN 2209 — Formaldehyde, solution (corrosive)
Placard: Corrosive. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2209 is Formaldehyde, solution (corrosive), a toxic corrosive formaldehyde solution assigned to ERG Guide 153. Vapor irritation, corrosive contact and carcinogenic exposure concern are key hazards.
Hazard overview: TOXIC and CORROSIVE formaldehyde solution; inhalation, ingestion or skin contact may cause severe injury. Vapor is irritating and can cause respiratory injury; formaldehyde is a carcinogenic exposure concern. Solution may be combustible depending on methanol content and concentration.
Response guidance: For a UN 2209 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 153. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff or vapor spread and base entry/fire-control actions on monitoring and local SOP.
Firefighter training notes: Training for UN 2209 should emphasize exposure routes, air monitoring, PPE selection, fire behavior, decontamination, runoff containment and ERG/SDS verification. Use ERG 153, SDS and local SOP.
Regulatory context: Formaldehyde, solution (corrosive) is regulated as a hazardous material for transportation and emergency response purposes. Storage, workplace exposure, emergency planning, spill reporting, waste handling and environmental requirements vary by exact product, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, container markings and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Formaldehyde, solution (corrosive) should be stored in tightly closed compatible containers in a secure, ventilated toxic-material area with secondary containment, restricted access and segregation from incompatible chemicals according to SDS.
UN 2209 Quick Details
Common Hazards of UN 2209
- TOXIC and CORROSIVE formaldehyde solution; inhalation, ingestion or skin contact may cause severe injury.
- Vapor is irritating and can cause respiratory injury; formaldehyde is a carcinogenic exposure concern.
- Solution may be combustible depending on methanol content and concentration.
- Skin and eye contact can cause burns and sensitization.
- Fire may produce carbon monoxide, formaldehyde vapor and irritating/toxic gases.
- Runoff may be toxic/corrosive and environmentally harmful.
- Containers may rupture or fail when heated.
Chemical Identity & Physical Properties
Clear, colorless to slightly cloudy aqueous solution with a pungent, irritating odor. Typically contains 37-50% formaldehyde by weight with methanol as a stabilizer.
| Also known as | FormalinMethanalMethyl aldehydeMethylene oxideFormic aldehydeOxomethane |
| CAS Number | 50-00-0 |
| Appearance | Clear, colorless to slightly cloudy aqueous solution with a pungent, irritating odor. Typically contains 37-50% formaldehyde by weight with methanol as a stabilizer. |
| Flash Point | 85C (185F) for 37% solution; varies with concentration |
| Boiling Point | 96-101C (205-214F) depending on concentration |
| Vapor Density | 1.03-1.09 (heavier than air) |
| Water Reactivity | Miscible with water; no violent reaction but dilution generates heat |
Fireground Response Guidance — UN 2209
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, dust, mist, fire or confined-space exposure. Wear chemical-resistant gloves, eye/face protection and protective clothing selected from SDS; avoid skin contact.
Isolation & Evacuation
First Actions for a UN 2209 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing gas, vapor, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers or spilled/released material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or release area and expand the perimeter for fire involvement, vapor/gas spread, cylinder heating, oxidizer reaction or unknown product identity.
- Use ERG Guide 153, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2209 — Formaldehyde, solution (corrosive)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.