UN 2429 — Calcium chlorate, aqueous solution
Placard: Oxidizer. ERG Guide 140. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2429 is Calcium chlorate, aqueous solution, an aqueous oxidizer solution assigned to ERG Guide 140. Contamination or drying can make the fire and decomposition hazard worse.
Hazard overview: OXIDIZING chlorate solution; can accelerate burning and make combustibles ignite more easily. May decompose violently if heated, concentrated by evaporation, contaminated or involved in fire. Contact with fuels, organics, acids, sulfur, powders or reducing agents can create fire or explosion hazards.
Response guidance: For UN 2429, isolate the area, remove combustibles and prevent contamination with fuel, oil or organics. Cool containers from protection, use water-based cooling/flooding tactics when safe and follow ERG 140.
Firefighter training notes: Training for UN 2429 should emphasize oxidizer contamination control, heat/decomposition signs, incompatible fuels/organics, container cooling, evacuation and runoff control. Use ERG 140, SDS and local SOP.
Regulatory context: Calcium chlorate, aqueous solution 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: Calcium chlorate, aqueous solution should be stored in compatible oxidizer-rated containers with temperature control where required, away from fuels, oils, organics, reducing agents, acids where incompatible and combustible contamination.
UN 2429 Quick Details
Common Hazards of UN 2429
- OXIDIZING chlorate solution; can accelerate burning and make combustibles ignite more easily.
- May decompose violently if heated, concentrated by evaporation, contaminated or involved in fire.
- Contact with fuels, organics, acids, sulfur, powders or reducing agents can create fire or explosion hazards.
- Dried residues or crystallized material may be more sensitive than the original solution.
- Fire may produce chlorine/oxygen-containing irritating or toxic gases.
- Containers may rupture or explode when heated.
- Runoff may carry oxidizer contamination and create environmental/fire hazards.
Chemical Identity & Physical Properties
Clear to pale yellow aqueous solution with no distinct odor. Liquid at room temperature, typically supplied in concentrations up to 50% by weight.
| Also known as | Calcium chlorate solutionChloric acid calcium salt solutionCalcium chlorate aqueous |
| CAS Number | 10137-74-3 |
| Appearance | Clear to pale yellow aqueous solution with no distinct odor. Liquid at room temperature, typically supplied in concentrations up to 50% by weight. |
| Flash Point | Not applicable (non-flammable oxidizer solution) |
| Boiling Point | Approximately 100C (212F), varies with concentration |
| Vapor Density | Not applicable (aqueous solution) |
| Water Reactivity | Already in aqueous solution; dissolves readily in water. Solution is stable but oxidizing. |
Fireground Response Guidance — UN 2429
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for fire, decomposition fumes or confined spaces. Wear chemical-resistant clothing, eye/face protection and thermal protection for hot solution.
Isolation & Evacuation
First Actions for a UN 2429 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 fuels, oils, organics, reducing agents and combustible contamination away from the oxidizer.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 140, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2429 — Calcium chlorate, aqueous solutionUse 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.