UN 1802 — Perchloric acid, with not more than 50% acid
Placard: Corrosive. ERG Guide 157. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1802 is Perchloric acid, with not more than 50% acid, a Class 8 corrosive oxidizing acid assigned to ERG Guide 157. It is less concentrated than higher-strength perchloric acid but still requires strict separation from organics and combustibles.
Hazard overview: UN 1802 presents corrosive burn, oxidizer, heat-on-dilution and reactive-residue hazards. Contamination with organic material, reducing agents or combustible absorbents can create dangerous reaction conditions.
Response guidance: For a UN 1802 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 157. Establish incident command, isolate the area, stay upwind, prevent incompatible contact, control runoff and choose entry or fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1802 should emphasize oxidizing acid behavior, incompatibility with organics/combustibles, residue drying hazards, fume control and runoff containment. Use ERG 157, SDS and local SOP.
Regulatory context: Perchloric acid, with not more than 50% 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 concentration, formulation, 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 not more than 50% acid should be stored in compatible corrosion-resistant containers in a clean, cool, well-ventilated oxidizing-acid area away from organics, combustibles, reducing agents, metals where incompatible, heat and contamination. Avoid absorbents or residues that could dry and concentrate.
UN 1802 Quick Details
Common Hazards of UN 1802
- CORROSIVE oxidizing acid solution; inhalation, ingestion or skin/eye contact may cause severe injury.
- Even at not more than 50% acid, contamination with organics, combustibles or reducing agents may create dangerous reaction hazards.
- Dilution with water may generate heat and increase fuming.
- Heating, drying or concentration of residues may increase oxidizing/reactive hazards.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may be corrosive, oxidizing and environmentally hazardous.
- Containers may rupture or fail when heated.
Chemical Identity & Physical Properties
Colorless to pale yellow aqueous solution with a pungent, irritating odor. Fuming liquid at higher concentrations. Highly corrosive and oxidizing.
| Also known as | Perchloric acid solutionPerchloric acid aqueousHydrogen perchloratePerchloric acid ≤50% |
| CAS Number | 7601-90-3 |
| Appearance | Colorless to pale yellow aqueous solution with a pungent, irritating odor. Fuming liquid at higher concentrations. Highly corrosive and oxidizing. |
| Flash Point | Not applicable (non-flammable aqueous solution, though oxidizer) |
| Boiling Point | 203C (397F) at 72% concentration; lower concentrations boil closer to water |
| Vapor Density | Not applicable (aqueous solution) |
| Water Reactivity | Generates heat when diluted; concentrated acid reacts violently with organics and combustibles |
Fireground Response Guidance — UN 1802
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, mist, dust, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing selected from SDS for corrosive contact.
Isolation & Evacuation
First Actions for a UN 1802 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 or spray and avoid skin or eye contact.
- Keep organic materials, combustibles, reducing agents and contaminated absorbents away from the acid.
- 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, water reaction or unknown concentration is present.
- Use ERG Guide 157, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1802 — Perchloric acid, with not more than 50%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.