☣️ UN 2691 • CLASS 8
UN 2691 — Phosphorus pentabromide
Placard: Corrosive. ERG Guide 137. 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 2691 Quick Details
UN 2691
Product name: Phosphorus pentabromide
DOT Class: 8
Placard type: Corrosive
ERG Guide: 137 (check current ERG)
Initial isolation: ERG 137: isolate spill area 25m all directions; if involved in fire, isolate 800m and consider evacuation
Common Hazards of UN 2691
- CORROSIVE and/or TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
- Fire will produce irritating, corrosive and/or toxic gases.
- Reaction with water may generate much heat that will increase the concentration of fumes in the air.
- Contact with molten substance may cause severe burns to skin and eyes.
- Runoff from fire control or dilution water may cause environmental contamination.
- EXCEPT FOR ACETIC ANHYDRIDE (UN1715), THAT IS FLAMMABLE, some of these materials may
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- Substance will react with water (some violently), releasing corrosive and/or toxic gases and runoff.
Chemical Identity & Physical Properties
| Also known as | PentabromodiphosphorusPhosphoric bromidePBr5 |
| CAS Number | 7789-69-7 |
| Appearance | Yellow to reddish-yellow crystalline solid with a pungent, irritating odor. Fumes in moist air. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | 106C (223F) decomposes |
| Vapor Density | Not applicable (solid, but evolves dense corrosive fumes) |
| Water Reactivity | Reacts violently with water releasing heat and toxic/corrosive hydrogen bromide and phosphoric acid fumes |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2691
Extinguishing Media
Dry chemical, sand, dry powder; do not use water or foam
PPE Requirements
⚠️ Level B minimum; full-face SCBA required; acid-resistant suit, boots, gloves due to corrosive fumes
Isolation & Evacuation
ERG 137: isolate spill area 25m all directions; if involved in fire, isolate 800m and consider evacuation
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 137).
First Actions for a UN 2691 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 2691 — Phosphorus pentabromideHAZMAT RADIO NOTE — UN 2691
Product: Phosphorus pentabromide
Class 8 / Corrosive / ERG 137
PPE: Level B minimum; full-face SCBA required; acid-resistant suit, boots, gloves due to corrosive fumes
ISOLATION: ERG 137: isolate spill area 25m all directions; if involved in fire, isolate 800m and consider evacuation
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 2691 — Phosphorus pentabromide
Class: 8 | Placard: Corrosive | ERG Guide: 137
Appearance: Yellow to reddish-yellow crystalline solid with a pungent, irritating odor. Fumes in moist air.
Water Reactivity: Reacts violently with water releasing heat and toxic/corrosive hydrogen bromide and phosphoric acid fumes
Extinguishing: Dry chemical, sand, dry powder; do not use water or foam
PPE: Level B minimum; full-face SCBA required; acid-resistant suit, boots, gloves due to corrosive fumes
Isolation: ERG 137: isolate spill area 25m all directions; if involved in fire, isolate 800m and consider evacuation
— Key Hazards —
• CORROSIVE and/or TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
• Fire will produce irritating, corrosive and/or toxic 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/2691 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2691 Phosphorus pentabromide Cls8 ERG137 | allfirefighter.com/hazmat/un/2691SMS / 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/2691
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Frequently Asked Questions about UN 2691
CORROSIVE and/or TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance Fire will produce irritating, corrosive and/or toxic gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Contact with molten substance may cause severe burns to skin and eyes. Runoff from fire control or dilution water may cause environmental contamination. EXCEPT FOR ACETIC ANHYDRIDE (UN1715), THAT IS FLAMMABLE, some of these materials may May ignite combustibles (wood, paper, oil, clothing, etc.). Substance will react with water (some violently), releasing corrosive and/or toxic gases and runoff.
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; full-face SCBA required; acid-resistant suit, boots, gloves due to corrosive fumes
Water reactivity: Reacts violently with water releasing heat and toxic/corrosive hydrogen bromide and phosphoric acid fumes. Recommended extinguishing: Dry chemical, sand, dry powder; do not use water or foam.
ERG Guide 137 recommendation: ERG 137: isolate spill area 25m all directions; if involved in fire, isolate 800m and consider evacuation
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 137 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.