☣️ UN 1826 • CLASS 8
Nitrating acid mixture, spent, with not more than 50% nitric acid
Placard: Corrosive. 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.
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Quick details
UN 1826
Class: 8
Placard type: Corrosive
ERG: Guide 157 (check current ERG)
Isolation: ERG 157: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m downwind
Chemical & Response Details
| Also known as | Spent nitrating acidSpent mixed acidWaste nitrating mixtureNitric-sulfuric acid waste |
| Appearance | Colorless to pale yellow or brownish liquid mixture, primarily containing sulfuric acid with residual nitric acid (≤50%). Corrosive with acrid, choking fumes. Dense, oily consistency typical of concentrated sulfuric acid. |
| Flash Point | Not applicable (non-flammable liquid) |
| Boiling Point | Varies with composition, typically >150C (302F) due to high sulfuric acid content |
| Vapor Density | Heavier than air; concentrated acid vapors settle in low areas |
| Water Reactivity | Reacts violently with water generating extreme heat and spattering; adds acid to water slowly, never reverse |
| Extinguishing | Dry chemical, soda ash, lime for neutralization; do not use water directly on spills |
| PPE | ⚠️ Level B minimum with acid-resistant suit; SCBA required; full face shield, butyl rubber or neoprene gloves; acid-resistant boots |
| Isolation | ERG 157: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m downwind |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.).
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- 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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UN 1826 — Nitrating acid mixture, spent, with not HAZMAT RADIO NOTE — UN 1826
Product: Nitrating acid mixture, spent, with not more than 50% nitric acid
Class 8 / Corrosive / ERG 157
PPE: Level B minimum with acid-resistant suit; SCBA required; full face shield, butyl rubber or neoprene gloves; acid-resistant boots
ISOLATION: ERG 157: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m downwind
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 1826 — Nitrating acid mixture, spent, with not more than 50% nitric acid
Class: 8 | Placard: Corrosive | ERG Guide: 157
Appearance: Colorless to pale yellow or brownish liquid mixture, primarily containing sulfuric acid with residual nitric acid (≤50%). Corrosive with acrid, choking fumes. Dense, oily consistency typical of concentrated sulfuric acid.
Water Reactivity: Reacts violently with water generating extreme heat and spattering; adds acid to water slowly, never reverse
Extinguishing: Dry chemical, soda ash, lime for neutralization; do not use water directly on spills
PPE: Level B minimum with acid-resistant suit; SCBA required; full face shield, butyl rubber or neoprene gloves; acid-resistant boots
Isolation: ERG 157: isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m downwind
— 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 —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/1826 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1826 Nitrating acid mixture, spent, with not more than 50% nitric acid Cls8 ERG157 | allfirefighter.com/hazmat/un/1826SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/1826
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FAQ
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.).
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level B minimum with acid-resistant suit; SCBA required; full face shield, butyl rubber or neoprene gloves; acid-resistant boots
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 157 and your department SOP/SOG for incident-specific protective actions.
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.