☣️ UN 3453 • CLASS 8
UN 3453 — Phosphoric acid, solid
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ 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.
UN 3453 Phosphoric acid, solid is assigned to ERG Guide 154. The exact risk depends on the shipment form, concentration and SDS, but responders should verify shipping papers before committing crews.
Hazard overview: Primary hazards for UN 3453 include: TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury or death.; Contact with molten substance may cause severe burns to skin and eyes.; Avoid any skin contact. Control ignition sources, avoid direct contact and keep personnel upwind.
Response guidance: For a UN 3453 incident, isolate the area, deny entry, stay upwind and use ERG Guide 154 with the shipping papers or SDS. Use compatible extinguishing media only and prevent contaminated runoff from spreading.
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UN 3453 Quick Details
UN 3453
Product name: Phosphoric acid, solid
DOT Class: 8
Placard type: Corrosive
ERG Guide: 154 (check current ERG)
Initial isolation: ERG 154: isolate spill 25m all directions; for large spills consider initial evacuation 100m downwind
Common Hazards of UN 3453
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury or death.
- 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 contamination.
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive.
- Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.).
- Corrosives in contact with metals may evolve flammable hydrogen gas.
Chemical Identity & Physical Properties
UN 3453 is described as: Colorless to pale yellow crystalline solid or syrupy liquid (depending on concentration and temperature). Odorless or slight odor. Hygroscopic.
| Also known as | Orthophosphoric acidO-Phosphoric acidWhite phosphoric acidPhosphoric acid anhydrous |
| CAS Number | 7664-38-2 |
| Appearance | Colorless to pale yellow crystalline solid or syrupy liquid (depending on concentration and temperature). Odorless or slight odor. Hygroscopic. |
| Flash Point | Not applicable (non-combustible) |
| Boiling Point | 158C (316F) for 85% solution; decomposes at higher temperatures |
| Vapor Density | Not applicable (solid at room temperature) |
| Water Reactivity | Dissolves in water, exothermic reaction generating heat. Corrosive solution forms. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3453
Extinguishing Media
Water spray, fog, or regular foam. Avoid direct water streams on molten material.
PPE Requirements
⚠️ Level B minimum for molten material; chemical resistant suit, gloves, boots; SCBA or APR with acid gas cartridges for vapors
PPE guidance for UN 3453: Level B minimum for molten material; chemical resistant suit, gloves, boots; SCBA or APR with acid gas cartridges for vapors
Isolation & Evacuation
ERG 154: isolate spill 25m all directions; for large spills consider initial evacuation 100m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 154).
First Actions for a UN 3453 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- 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 distance in the downwind direction as conditions require.
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📋 Copy & Share Field Card
UN 3453 — Phosphoric acid, solidHAZMAT RADIO NOTE — UN 3453
Product: Phosphoric acid, solid
Class 8 / Corrosive / ERG 154
PPE: Level B minimum for molten material; chemical resistant suit, gloves, boots; SCBA or APR with acid gas cartridges for vapors
ISOLATION: ERG 154: isolate spill 25m all directions; for large spills consider initial evacuation 100m 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 3453 — Phosphoric acid, solid
Class: 8 | Placard: Corrosive | ERG Guide: 154
Appearance: Colorless to pale yellow crystalline solid or syrupy liquid (depending on concentration and temperature). Odorless or slight odor. Hygroscopic.
Water Reactivity: Dissolves in water, exothermic reaction generating heat. Corrosive solution forms.
Extinguishing: Water spray, fog, or regular foam. Avoid direct water streams on molten material.
PPE: Level B minimum for molten material; chemical resistant suit, gloves, boots; SCBA or APR with acid gas cartridges for vapors
Isolation: ERG 154: isolate spill 25m all directions; for large spills consider initial evacuation 100m downwind
— Key Hazards —
• TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury or death.
• Contact with molten substance may cause severe burns to skin and eyes.
• Avoid any skin contact.
— First Actions —
• CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
• 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/phosphoric-acid-solid-un-3453 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3453 Phosphoric acid, solid Cls8 ERG154 | allfirefighter.com/hazmat/un/phosphoric-acid-solid-un-3453SMS / 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/phosphoric-acid-solid-un-3453
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Frequently Asked Questions about UN 3453
UN 3453 is Phosphoric acid, solid, a Class 8 hazardous material assigned to ERG Guide 154.
UN 3453 may burn or support fire depending on the product and fire conditions. Keep ignition sources away and follow ERG 154.
Dissolves in water, exothermic reaction generating heat. Corrosive solution forms.
Level B minimum for molten material; chemical resistant suit, gloves, boots; SCBA or APR with acid gas cartridges for vapors
ERG 154: isolate spill 25m all directions; for large spills consider initial evacuation 100m downwind
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.