☣️ UN 1802 • CLASS 8
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.
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⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
Perchloric acid is a colorless to pale yellow aqueous solution with a pungent, irritating odor. It is a toxic and corrosive substance that can cause severe injury or death if inhaled, ingested, or if it comes into contact with the skin or eyes.
Hazard overview: The substance is highly corrosive and oxidizing, and it can release toxic, corrosive, or flammable gases when it reacts with water or moist air. Prolonged exposure to the substance can cause severe injury or death.
Response guidance: In case of an emergency, evacuate the area immediately and call for professional help. Use water spray to dilute the substance, and use CO2 or dry chemical to extinguish the fire, avoiding organics and combustibles near the acid.
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UN 1802 Quick Details
UN 1802
Product name: Perchloric acid, with not more than 50% acid
DOT Class: 8
Placard type: Corrosive
ERG Guide: 157 (check current ERG)
Initial isolation: ERG 157: isolate spill 25-50m; evacuate 300m downwind if large spill; avoid contact with organics
Common Hazards of UN 1802
- TOXIC and/or CORROSIVE; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
- Reaction with water or moist air may release toxic, corrosive or flammable gases.
- Reaction with water may generate much heat that will increase the concentration of fumes in the air.
- Fire will produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive
- UN1802, UN2032, UN3084, UN3093, UN1796 (above 50%), UN1826 (above 50%), and UN2031 (above
- Vapors may accumulate in confined areas (basement, tanks, hopper/tank cars, etc.).
Chemical Identity & Physical Properties
Perchloric acid is a colorless to pale yellow aqueous solution with a pungent, irritating odor that fumes at higher concentrations.
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1802
Extinguishing Media
Water spray to dilute, CO2, dry chemical; avoid organics and combustibles near acid
PPE Requirements
⚠️ Level B minimum; SCBA, full face shield, acid-resistant suit, neoprene/butyl gloves required
Wear Level B minimum protective equipment, including SCBA, full face shield, acid-resistant suit, and neoprene/butyl gloves to prevent skin and eye contact with the substance.
Isolation & Evacuation
ERG 157: isolate spill 25-50m; evacuate 300m downwind if large spill; avoid contact with organics
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 157).
First Actions for a UN 1802 Incident
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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📋 Copy & Share Field Card
UN 1802 — Perchloric acid, with not more than 50%HAZMAT RADIO NOTE — UN 1802
Product: Perchloric acid, with not more than 50% acid
Class 8 / Corrosive / ERG 157
PPE: Level B minimum; SCBA, full face shield, acid-resistant suit, neoprene/butyl gloves required
ISOLATION: ERG 157: isolate spill 25-50m; evacuate 300m downwind if large spill; avoid contact with organics
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 1802 — Perchloric acid, with not more than 50% acid
Class: 8 | Placard: Corrosive | ERG Guide: 157
Appearance: Colorless to pale yellow aqueous solution with a pungent, irritating odor. Fuming liquid at higher concentrations. Highly corrosive and oxidizing.
Water Reactivity: Generates heat when diluted; concentrated acid reacts violently with organics and combustibles
Extinguishing: Water spray to dilute, CO2, dry chemical; avoid organics and combustibles near acid
PPE: Level B minimum; SCBA, full face shield, acid-resistant suit, neoprene/butyl gloves required
Isolation: ERG 157: isolate spill 25-50m; evacuate 300m downwind if large spill; avoid contact with organics
— Key Hazards —
• TOXIC and/or CORROSIVE; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
• Reaction with water or moist air may release toxic, corrosive or flammable gases.
• Reaction with water may generate much heat that will increase the concentration of fumes in the air.
— First Actions —
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/perchloric-acid-with-not-un-1802 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1802 Perchloric acid, with not more than 50% acid Cls8 ERG157 | allfirefighter.com/hazmat/un/perchloric-acid-with-not-un-1802SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/perchloric-acid-with-not-un-1802
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Frequently Asked Questions about UN 1802
Yes, UN 1802 is a toxic and corrosive substance that can cause severe injury or death.
UN 1802 generates heat when diluted, and concentrated acid reacts violently with organics and combustibles.
Level B minimum protective equipment, including SCBA, full face shield, acid-resistant suit, and neoprene/butyl gloves.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles.
This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.