☣️ UN 2809 • CLASS 8
UN 2809 — Mercury
Placard: Corrosive. ERG Guide 172. 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.
Mercury is a heavy liquid metal that can form mobile droplets and release toxic vapor. Small visible amounts can create significant contamination if spread by traffic or cleanup errors.
Hazard overview: The key hazard is inhalation of mercury vapor, especially in warm or poorly ventilated areas. Droplets can roll into cracks and keep releasing vapor until properly recovered.
Response guidance: Isolate the area, stop foot traffic and avoid sweeping or vacuuming. Ventilate if safe, contain droplets and request mercury-specific cleanup resources.
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UN 2809 Quick Details
UN 2809
Product name: Mercury
DOT Class: 8
Placard type: Corrosive
ERG Guide: 172 (check current ERG)
Initial isolation: ERG 172: isolate spill area at least 25m in all directions; evacuate immediate area; mercury vapor accumulates in low areas; requires specialized containment and cleanup
Common Hazards of UN 2809
- Mercury releases toxic vapor even at room temperature, with vapor accumulation in low or poorly ventilated areas.
- Droplets spread easily and contaminate cracks, drains, clothing and equipment.
- Heating or fire greatly increases mercury vapor generation.
- Contact can contaminate skin and PPE; inhalation is the main acute response concern.
- Mercury is non-combustible, but contaminated fire debris can remain hazardous.
- Runoff and cleanup waste can pollute waterways and must be contained.
- Improper vacuuming, sweeping or washing can spread contamination.
Chemical Identity & Physical Properties
Mercury is a silver-white, odorless liquid metal with high surface tension. It forms round droplets that move easily across hard surfaces.
| Also known as | Elemental mercuryQuicksilverLiquid silverHydrargyrumMetallic mercury |
| CAS Number | 7439-97-6 |
| Appearance | Silver-white, heavy, odorless liquid metal at room temperature. High surface tension causes it to form spherical droplets that roll easily. |
| Flash Point | Not applicable (liquid metal, non-combustible) |
| Boiling Point | 357C (674F) |
| Vapor Density | 6.9 (much heavier than air) |
| Water Reactivity | No significant reaction with water, but forms toxic vapor at all temperatures |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2809
Extinguishing Media
Not applicable for extinguishment (non-combustible); mercury spills require specialized cleanup, not foam
PPE Requirements
⚠️ Level B minimum with vapor-tight chemical suit; SCBA required; avoid all skin contact; use mercury-specific respirator cartridges for vapor protection
Use SCBA or mercury-rated respiratory protection as directed by monitoring, plus chemical-resistant gloves and protective clothing. Avoid carrying contamination out of the hot zone.
Isolation & Evacuation
ERG 172: isolate spill area at least 25m in all directions; evacuate immediate area; mercury vapor accumulates in low areas; requires specialized containment and cleanup
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 172).
First Actions for a UN 2809 Incident
- Call 911 and the emergency response number shown on the shipping papers or container documents.
- Keep unauthorized personnel away and establish an isolation perimeter before entry.
- Stay upwind, uphill and upstream; keep responders out of vapors, dusts and runoff.
- Avoid breathing vapors, dust, mist or smoke and avoid skin or eye contact.
- Do not touch damaged containers or spilled material unless properly trained and protected.
- Ventilate confined spaces only when personnel are trained, equipped and monitored.
- Use ERG guidance, SDS, shipping papers and air monitoring to confirm protective actions.
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📋 Copy & Share Field Card
UN 2809 — MercuryHAZMAT RADIO NOTE — UN 2809
Product: Mercury
Class 8 / Corrosive / ERG 172
PPE: Level B minimum with vapor-tight chemical suit; SCBA required; avoid all skin contact; use mercury-specific respirator cartridges for vapor protection
ISOLATION: ERG 172: isolate spill area at least 25m in all directions; evacuate immediate area; mercury vapor accumulates in low areas; requires specialized containment and cleanup
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 2809 — Mercury
Class: 8 | Placard: Corrosive | ERG Guide: 172
Appearance: Silver-white, heavy, odorless liquid metal at room temperature. High surface tension causes it to form spherical droplets that roll easily.
Water Reactivity: No significant reaction with water, but forms toxic vapor at all temperatures
Extinguishing: Not applicable for extinguishment (non-combustible); mercury spills require specialized cleanup, not foam
PPE: Level B minimum with vapor-tight chemical suit; SCBA required; avoid all skin contact; use mercury-specific respirator cartridges for vapor protection
Isolation: ERG 172: isolate spill area at least 25m in all directions; evacuate immediate area; mercury vapor accumulates in low areas; requires specialized containment and cleanup
— Key Hazards —
• Mercury releases toxic vapor even at room temperature, with vapor accumulation in low or poorly ventilated areas.
• Droplets spread easily and contaminate cracks, drains, clothing and equipment.
• Heating or fire greatly increases mercury vapor generation.
— First Actions —
• Call 911 and the emergency response number shown on the shipping papers or container documents.
• Keep unauthorized personnel away and establish an isolation perimeter before entry.
• Stay upwind, uphill and upstream; keep responders out of vapors, dusts and runoff.
• Avoid breathing vapors, dust, mist or smoke and avoid skin or eye contact.
SOURCE: allfirefighter.com/hazmat/un/mercury-un-2809 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN2809 Mercury Cls8 ERG172 | ERG 172: isolate spill area at least 25m in all directions; evacuate immediate a | allfirefighter.com/hazmat/un/mercury-un-2809SMS / 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/mercury-un-2809
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Frequently Asked Questions about UN 2809
No. Mercury is not combustible, but heating increases toxic vapor production.
Droplets can spread into cracks and keep releasing toxic vapor over time.
No. Ordinary vacuums can aerosolize mercury and contaminate equipment.
Inhalation of mercury vapor is the primary concern during emergency response.
Use mercury-specific collection, monitoring and waste handling procedures.
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.