☣️ UN 3412 • CLASS 8
UN 3412 — Formic acid, with not less than 10% but not more than 85% acid
Placard: Corrosive. ERG Guide 153. 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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UN 3412 Quick Details
UN 3412
Product name: Formic acid, with not less than 10% but not more than 85% acid
DOT Class: 8
Placard type: Corrosive
ERG Guide: 153 (check current ERG)
Initial isolation: ERG 153: Small spill isolate 30m all directions; large spill isolate 100m all directions, evacuate 300m downwind if fire or major release
Common Hazards of UN 3412
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears).
- Contact with molten substance may cause severe burns to skin and eyes.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
- Combustible material: may burn but does not ignite readily.
- When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
Chemical Identity & Physical Properties
| Also known as | Methanoic acidHydrogen carboxylic acidFormylic acidAminic acid |
| CAS Number | 64-18-6 |
| Appearance | Colorless fuming liquid with a pungent, penetrating odor. Highly corrosive to metals and tissue. Miscible with water in all proportions. |
| Flash Point | 69°C (156°F) for concentrations around 85%; lower concentrations have higher flash points |
| Boiling Point | 100.8°C (213°F) for pure formic acid; varies with concentration |
| Vapor Density | 1.59 (heavier than air) |
| Water Reactivity | Miscible with water; dilution generates heat but no violent reaction. Use water spray to dilute spills. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3412
Extinguishing Media
Alcohol-resistant foam, CO2, dry chemical; avoid direct water jet on concentrated acid
PPE Requirements
⚠️ Level B minimum; SCBA required; chemical-resistant suit, gloves, and boots. Acid-resistant apron recommended for splash protection.
Isolation & Evacuation
ERG 153: Small spill isolate 30m all directions; large spill isolate 100m all directions, evacuate 300m downwind if fire or major release
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 153).
First Actions for a UN 3412 Incident
- 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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📋 Copy & Share Field Card
UN 3412 — Formic acid, with not less than 10% butHAZMAT RADIO NOTE — UN 3412
Product: Formic acid, with not less than 10% but not more than 85% acid
Class 8 / Corrosive / ERG 153
PPE: Level B minimum; SCBA required; chemical-resistant suit, gloves, and boots. Acid-resistant apron recommended for splash protection.
ISOLATION: ERG 153: Small spill isolate 30m all directions; large spill isolate 100m all directions, evacuate 300m downwind if fire or major release
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 3412 — Formic acid, with not less than 10% but not more than 85% acid
Class: 8 | Placard: Corrosive | ERG Guide: 153
Appearance: Colorless fuming liquid with a pungent, penetrating odor. Highly corrosive to metals and tissue. Miscible with water in all proportions.
Water Reactivity: Miscible with water; dilution generates heat but no violent reaction. Use water spray to dilute spills.
Extinguishing: Alcohol-resistant foam, CO2, dry chemical; avoid direct water jet on concentrated acid
PPE: Level B minimum; SCBA required; chemical-resistant suit, gloves, and boots. Acid-resistant apron recommended for splash protection.
Isolation: ERG 153: Small spill isolate 30m all directions; large spill isolate 100m all directions, evacuate 300m downwind if fire or major release
— Key Hazards —
• TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
• Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears).
• Contact with molten substance may cause severe burns to skin and eyes.
— 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/3412 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3412 Formic acid, with not less than 10% but not more than 85% acid Cls8 ERG153 | allfirefighter.com/hazmat/un/3412SMS / 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/3412
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Frequently Asked Questions about UN 3412
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears). Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental Combustible material: may burn but does not ignite readily. When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
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; SCBA required; chemical-resistant suit, gloves, and boots. Acid-resistant apron recommended for splash protection.
Water reactivity: Miscible with water; dilution generates heat but no violent reaction. Use water spray to dilute spills.. Recommended extinguishing: Alcohol-resistant foam, CO2, dry chemical; avoid direct water jet on concentrated acid.
ERG Guide 153 recommendation: ERG 153: Small spill isolate 30m all directions; large spill isolate 100m all directions, evacuate 300m downwind if fire or major release
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 153 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.