UN 1873 — Perchloric acid, with more than 50% but not more than 72% acid
Placard: Oxidizer. ERG Guide 143. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1873 is Perchloric acid, with more than 50% but not more than 72% acid, a hazardous material assigned to ERG Guide 143. Responders should verify the exact product with shipping papers, package markings and SDS before close action.
Hazard overview: UN 1873 presents hazards that depend on formulation, packaging and incident conditions. Use ERG, SDS and incident command to set isolation, PPE and control actions.
Response guidance: For a UN 1873 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 143. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff or vapor spread and choose entry/fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1873 should emphasize exposure routes, air monitoring, PPE selection, decontamination, runoff containment and ERG/SDS verification. Use ERG 143, SDS and local SOP.
Regulatory context: Perchloric acid, with more than 50% but not more than 72% acid is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by formulation, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Perchloric acid, with more than 50% but not more than 72% acid should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated hazardous-material area according to SDS and local procedures.
UN 1873 Quick Details
Common Hazards of UN 1873
- Hazards depend on the exact product, packaging and incident conditions.
- Verify the material using shipping papers, labels and SDS before close action.
- Fire may produce irritating or toxic smoke.
- Containers may fail or rupture when heated.
Chemical Identity & Physical Properties
Colorless to slightly yellow, fuming liquid with a sharp, acrid odor. Highly corrosive and oxidizing at room temperature.
| Also known as | Perchloric acidChloric acid, per-Hyperchloric acidDioxonium perchlorate |
| CAS Number | 7601-90-3 |
| Appearance | Colorless to slightly yellow, fuming liquid with a sharp, acrid odor. Highly corrosive and oxidizing at room temperature. |
| Flash Point | Not applicable (strong oxidizer, not flammable itself) |
| Boiling Point | 203C (397F) at 70% concentration, decomposes |
| Vapor Density | 3.5 (heavier than air) |
| Water Reactivity | Miscible with water, generates heat on dilution; dilution reduces explosive hazard |
Fireground Response Guidance — UN 1873
Extinguishing Media
PPE Requirements
Use protective equipment selected from SDS, monitoring results and incident command.
Isolation & Evacuation
First Actions for a UN 1873 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 vapors, fumes, dust, mist, smoke or gas and avoid skin or eye contact.
- Do not touch or walk through spilled 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 leak area and expand the perimeter if vapor, dust, fire involvement, gas accumulation or unknown concentration is present.
- Use ERG Guide 143, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1873 — Perchloric acid, with more than 50% butUse 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.