☣️ 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 asPerchloric acid solutionPerchloric acid aqueousHydrogen perchloratePerchloric acid ≤50%
CAS Number7601-90-3
AppearanceColorless to pale yellow aqueous solution with a pungent, irritating odor. Fuming liquid at higher concentrations. Highly corrosive and oxidizing.
Flash PointNot applicable (non-flammable aqueous solution, though oxidizer)
Boiling Point203C (397F) at 72% concentration; lower concentrations boil closer to water
Vapor DensityNot applicable (aqueous solution)
Water ReactivityGenerates 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.

SMS WhatsApp
=== 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.

SMS (short)
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

Related UN Numbers in Class 8

Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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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.