☣️ UN 2798 • CLASS 8
Benzene phosphorus dichloride
Placard: Corrosive. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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 2798
Class: 8
Placard type: Corrosive
ERG: Guide 137 (check current ERG)
Isolation: ERG 137: Initial isolation 50m in all directions; Protective Action Distance 0.1 km (day) / 0.3 km (night) for spills; evacuate immediate area if fire involved
Chemical & Response Details
| Also known as | Benzenephosphonic dichloridePhenylphosphonic dichloridePhenylphosphonyl dichlorideDichlorophenylphosphine oxide |
| CAS Number | 824-72-6 |
| Appearance | Colorless to pale yellow liquid with a pungent, irritating odor. Fumes in moist air due to reaction with atmospheric moisture. |
| Flash Point | Not readily flammable but may decompose on heating |
| Boiling Point | 258C (496F) with decomposition |
| Vapor Density | 6.6 (heavier than air) |
| Water Reactivity | Reacts vigorously with water producing heat and corrosive fumes of hydrogen chloride and phosphonic acid |
| Extinguishing | Dry chemical, CO2, dry sand; avoid water-based agents due to vigorous hydrolysis reaction |
| PPE | ⚠️ Level B minimum required; SCBA mandatory; full chemical-resistant suit; neoprene or butyl rubber gloves; face shield with goggles |
| Isolation | ERG 137: Initial isolation 50m in all directions; Protective Action Distance 0.1 km (day) / 0.3 km (night) for spills; evacuate immediate area if fire involved |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
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 2798 — Benzene phosphorus dichloride HAZMAT RADIO NOTE — UN 2798
Product: Benzene phosphorus dichloride
Class 8 / Corrosive / ERG 137
PPE: Level B minimum required; SCBA mandatory; full chemical-resistant suit; neoprene or butyl rubber gloves; face shield with goggles
ISOLATION: ERG 137: Initial isolation 50m in all directions; Protective Action Distance 0.1 km (day) / 0.3 km (night) for spills; evacuate immediate area if fire involved
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 2798 — Benzene phosphorus dichloride
Class: 8 | Placard: Corrosive | ERG Guide: 137
Appearance: Colorless to pale yellow liquid with a pungent, irritating odor. Fumes in moist air due to reaction with atmospheric moisture.
Water Reactivity: Reacts vigorously with water producing heat and corrosive fumes of hydrogen chloride and phosphonic acid
Extinguishing: Dry chemical, CO2, dry sand; avoid water-based agents due to vigorous hydrolysis reaction
PPE: Level B minimum required; SCBA mandatory; full chemical-resistant suit; neoprene or butyl rubber gloves; face shield with goggles
Isolation: ERG 137: Initial isolation 50m in all directions; Protective Action Distance 0.1 km (day) / 0.3 km (night) for spills; evacuate immediate area if fire involved
— 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/2798 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2798 Benzene phosphorus dichloride Cls8 ERG137 | allfirefighter.com/hazmat/un/2798SMS / 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/2798
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FAQ
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 required; SCBA mandatory; full chemical-resistant suit; neoprene or butyl rubber gloves; face shield with goggles
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.