UN 2208 — Calcium hypochlorite mixture, dry, with more than 10% but not more than 39% available chlorine
Placard: Oxidizer. ERG Guide 140. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2208 is Calcium hypochlorite mixture, dry, with more than 10% but not more than 39% available chlorine, a dry oxidizing hypochlorite mixture assigned to ERG Guide 140. Moisture or incompatible chemicals can release chlorine and heat.
Hazard overview: OXIDIZING dry calcium hypochlorite mixture; can accelerate burning and ignite combustibles. Contact with acids, ammonia, organic materials, oils, fuels or reducing agents can release toxic chlorine or cause fire. Water or moisture can generate heat and release chlorine-containing gases; wet material may decompose.
Response guidance: For a UN 2208 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 140. 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 2208 should emphasize oxidizer contamination control, chlorine release, incompatible chemical segregation, water-use decisions, runoff control and dust exposure. Use ERG 140, SDS and local SOP.
Regulatory context: Calcium hypochlorite mixture, dry, with more than 10% but not more than 39% available chlorine 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: Calcium hypochlorite mixture, dry, with more than 10% but not more than 39% available chlorine should be stored cool, dry and segregated from acids, ammonia, organic materials, oils, fuels, reducing agents and combustible contamination. Keep containers closed and protect from moisture, heat and contamination.
UN 2208 Quick Details
Common Hazards of UN 2208
- OXIDIZING dry calcium hypochlorite mixture; can accelerate burning and ignite combustibles.
- Contact with acids, ammonia, organic materials, oils, fuels or reducing agents can release toxic chlorine or cause fire.
- Water or moisture can generate heat and release chlorine-containing gases; wet material may decompose.
- May decompose violently if heated, contaminated or confined.
- Dust or solution can burn eyes, skin and respiratory tissue.
- Runoff may be corrosive, oxidizing and toxic to waterways.
- Containers may rupture or explode when heated or contaminated.
Chemical Identity & Physical Properties
White to light gray granular powder or tablets with a strong chlorine odor. Solid oxidizer at room temperature.
| Also known as | Calcium hypochlorite dry mixCal hypo granularHTHChlorinating powderCalcium oxychloride mixture |
| Appearance | White to light gray granular powder or tablets with a strong chlorine odor. Solid oxidizer at room temperature. |
| Flash Point | Not applicable (non-flammable oxidizer) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts with water releasing heat and chlorine gas; may ignite combustible materials when wet |
Fireground Response Guidance — UN 2208
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for dust, chlorine gas, fire or decomposition exposure. Wear chemical-resistant gloves, boots, eye/face protection and clothing compatible with oxidizers.
Isolation & Evacuation
First Actions for a UN 2208 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.
- Keep acids, ammonia, organics, oils, fuels and reducing agents away from the oxidizer.
- 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 140, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2208 — Calcium hypochlorite mixture, dry, withUse 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.