☣️ UN 2790 • CLASS 8
UN 2790 — Acetic acid, solution, more than 10% but not more than 80% acid
Placard: Corrosive. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ 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.
Acetic acid solution, more than 10% but not more than 80% acid is a corrosive aqueous acid. The exact concentration affects vapor, burn and fire-control concerns.
Hazard overview: Acetic acid solution is corrosive; severity depends on concentration within the declared range. Mist or vapor can irritate the nose, throat and lungs. Skin and eye contact can cause burns, especially at higher concentrations.
Response guidance: Isolate the release, avoid vapors or mist and contain acidic runoff. Use SCBA when airborne exposure is possible and wear acid-resistant protective clothing for any contact risk.
Firefighter training notes: Train responders to identify the UN number, product name, placard, container type and exposure route before committing personnel to the hot zone.
Regulatory context: Use the proper DOT shipping description, ERG guide, SDS and site-specific response plan; do not substitute this summary for regulatory compliance.
Storage & handling: Store in compatible acid containers away from bases, oxidizers, reactive metals, heat and drains.
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UN 2790 Quick Details
UN 2790
Product name: Acetic acid, solution, more than 10% but not more than 80% acid
DOT Class: 8
Placard type: Corrosive
ERG Guide: 153 (check current ERG)
Initial isolation: Use ERG 153 initially and adjust for concentration, release size, ventilation and corrosive runoff pathways.
Common Hazards of UN 2790
- Acetic acid solution is corrosive; severity depends on concentration within the declared range.
- Mist or vapor can irritate the nose, throat and lungs.
- Skin and eye contact can cause burns, especially at higher concentrations.
- Contact with some metals can release flammable hydrogen gas.
- Heating can increase corrosive vapor generation and container pressure.
- Runoff may be acidic and harmful to drains or waterways.
- Combustibility is lower than stronger acid solutions but should be verified by SDS.
- Final response depends on exact acid concentration and packaging.
Chemical Identity & Physical Properties
Clear, colorless liquid with a pungent, vinegar-like odor. Corrosive to skin and eyes.
| Also known as | Glacial acetic acidEthanoic acidVinegar acidMethanecarboxylic acid |
| CAS Number | 64-19-7 |
| Appearance | Clear, colorless liquid with a pungent, vinegar-like odor. Corrosive to skin and eyes. |
| Flash Point | 39C (103F) for concentrations above 25%; higher concentrations have lower flash points |
| Boiling Point | 118C (244F) for pure acetic acid; varies with concentration |
| Vapor Density | 2.1 (heavier than air) |
| Water Reactivity | Miscible with water; dilution may release heat. Control runoff and verify concentration before neutralization. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2790
Extinguishing Media
Water spray, dry chemical, CO2 or foam may be used depending on concentration and surrounding fire conditions.
PPE Requirements
⚠️ SCBA when mist or vapor is present; acid-resistant gloves, boots, suit and eye/face protection for contact risk.
Level B minimum; SCBA required; acid-resistant gloves and suit; full face shield
Isolation & Evacuation
Use ERG 153 initially and adjust for concentration, release size, ventilation and corrosive runoff pathways.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 153).
First Actions for a UN 2790 Incident
- Call 911 and the emergency response number shown on the shipping papers.
- Keep unauthorized personnel away and establish an initial isolation perimeter.
- Stay upwind, uphill and upstream; avoid low areas where vapors or runoff may collect.
- Avoid breathing vapors, dust, mist or smoke and prevent skin and eye contact.
- Do not touch damaged packages, leaking containers or spilled material without appropriate PPE.
- Ventilate confined spaces only when responders are trained, equipped and monitoring conditions.
- Use ERG, SDS, shipping papers and air monitoring to set final isolation, evacuation and decon actions.
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UN 2790 — Acetic acid, solution, more than 10% butHAZMAT RADIO NOTE — UN 2790
Product: Acetic acid, solution, more than 10% but not more than 80% acid
Class 8 / Corrosive / ERG 153
PPE: SCBA when mist or vapor is present; acid-resistant gloves, boots, suit and eye/face protection for contact risk.
ISOLATION: Use ERG 153 initially and adjust for concentration, release size, ventilation and corrosive runoff pathways.
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 2790 — Acetic acid, solution, more than 10% but not more than 80% acid
Class: 8 | Placard: Corrosive | ERG Guide: 153
Appearance: Clear, colorless liquid with a pungent, vinegar-like odor. Corrosive to skin and eyes.
Water Reactivity: Miscible with water; dilution may release heat. Control runoff and verify concentration before neutralization.
Extinguishing: Water spray, dry chemical, CO2 or foam may be used depending on concentration and surrounding fire conditions.
PPE: SCBA when mist or vapor is present; acid-resistant gloves, boots, suit and eye/face protection for contact risk.
Isolation: Use ERG 153 initially and adjust for concentration, release size, ventilation and corrosive runoff pathways.
— Key Hazards —
• Acetic acid solution is corrosive; severity depends on concentration within the declared range.
• Mist or vapor can irritate the nose, throat and lungs.
• Skin and eye contact can cause burns, especially at higher concentrations.
— First Actions —
• Call 911 and the emergency response number shown on the shipping papers.
• Keep unauthorized personnel away and establish an initial isolation perimeter.
• Stay upwind, uphill and upstream; avoid low areas where vapors or runoff may collect.
• Avoid breathing vapors, dust, mist or smoke and prevent skin and eye contact.
SOURCE: allfirefighter.com/hazmat/un/acetic-acid-solution-more-un-2790 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN2790 Acetic acid, solution, more than 10% but not more than 80% acid Cls8 ERG153 | allfirefighter.com/hazmat/un/acetic-acid-solution-more-un-2790SMS / 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/acetic-acid-solution-more-un-2790
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Frequently Asked Questions about UN 2790
UN 2790 covers Acetic acid, solution, more than 10% but not more than 80% acid. Use the shipping papers and SDS to confirm the exact product before choosing tactics.
Yes. Exposure may be harmful or fatal by inhalation, ingestion or skin absorption, depending on concentration and formulation.
Yes. Direct contact can injure skin and eyes, and vapors or mist may damage the respiratory tract.
It is not classed as a flammable liquid, but it may decompose or involve combustible packaging in a fire.
The solution is water-miscible; dilution may release heat and should be done only under controlled response guidance.
Alcohol-resistant foam, CO2, dry chemical; water spray for cooling only
Use SCBA and chemical-resistant protective clothing. Level A or B may be needed when vapors, splash risk or product identity is uncertain.
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.