☣️ UN 3453 • CLASS 8
Phosphoric acid, solid
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 3453
Class: 8
Placard type: Corrosive
ERG: Guide 154 (check current ERG)
Isolation: ERG 154: isolate spill 25m all directions; for large spills consider initial evacuation 100m downwind
Chemical & Response Details
| 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. |
| 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 |
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 skin contact with material may cause severe injury
- 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
- 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.
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 3453 — Phosphoric acid, solid HAZMAT 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
• Contact with molten substance may cause severe burns to skin and eyes.
• Avoid any skin contact.
— 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/3453 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3453 Phosphoric acid, solid Cls8 ERG154 | ERG 154: isolate spill 25m all directions; for large spills consider initial eva | allfirefighter.com/hazmat/un/3453SMS / 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/3453
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FAQ
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury 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 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.
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 for molten material; chemical resistant suit, gloves, boots; SCBA or APR with acid gas cartridges for vapors
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 154 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.