☣️ UN 2664 • CLASS 6
Dibromomethane
Placard: Toxic. 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 2664
Class: 6
Placard type: Toxic
ERG: Guide 160 (check current ERG)
Isolation: ERG 160: isolate spill 25-50m all directions; if tank/rail car involved in fire isolate 800m and consider evacuation
Chemical & Response Details
| Also known as | Methylene dibromideMethylene bromideDibromomethaneDBMMethane dibromide |
| CAS Number | 74-95-3 |
| Appearance | Colorless to pale yellow liquid with a sweet, chloroform-like odor. Denser than water and will sink. |
| Flash Point | Not applicable (non-flammable liquid) |
| Boiling Point | 97C (207F) |
| Vapor Density | 5.8 (heavier than air) |
| Water Reactivity | No significant reaction with water; slightly soluble |
| Extinguishing | Dry chemical, CO2, water spray, foam; non-flammable but vapor control may be needed |
| PPE | ⚠️ Level B minimum with SCBA required in confined spaces or high vapor concentrations; chemical-resistant suit and gloves |
| Isolation | ERG 160: isolate spill 25-50m all directions; if tank/rail car involved in fire isolate 800m and consider evacuation |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Toxic by ingestion.
- Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas.
- Exposure in an enclosed area may be very harmful.
- Contact may irritate or burn skin and eyes.
- Fire may produce irritating and/or toxic gases.
- Runoff from fire control or dilution water may cause environmental contamination.
- Some of these materials may burn, but none ignite readily.
- Most vapors are heavier than air.
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.
- Many gases are heavier than air and will spread along the ground and collect in low or confined areas
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 50 meters (150 feet) in all directions.
- Consider initial downwind evacuation for at least 100 meters (330 feet).
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UN 2664 — Dibromomethane HAZMAT RADIO NOTE — UN 2664
Product: Dibromomethane
Class 6 / Toxic / ERG 160
PPE: Level B minimum with SCBA required in confined spaces or high vapor concentrations; chemical-resistant suit and gloves
ISOLATION: ERG 160: isolate spill 25-50m all directions; if tank/rail car 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 2664 — Dibromomethane
Class: 6 | Placard: Toxic | ERG Guide: 160
Appearance: Colorless to pale yellow liquid with a sweet, chloroform-like odor. Denser than water and will sink.
Water Reactivity: No significant reaction with water; slightly soluble
Extinguishing: Dry chemical, CO2, water spray, foam; non-flammable but vapor control may be needed
PPE: Level B minimum with SCBA required in confined spaces or high vapor concentrations; chemical-resistant suit and gloves
Isolation: ERG 160: isolate spill 25-50m all directions; if tank/rail car involved in fire isolate 800m and consider evacuation
— Key Hazards —
• Toxic by ingestion.
• Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas.
• Exposure in an enclosed area may be very harmful.
— 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.
• Many gases are heavier than air and will spread along the ground and collect in low or confined areas
SOURCE: allfirefighter.com/hazmat/un/2664 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2664 Dibromomethane Cls6 ERG160 | ERG 160: isolate spill 25-50m all directions; if tank/rail car involved in fire | allfirefighter.com/hazmat/un/2664SMS / 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/2664
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FAQ
Toxic by ingestion. Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas. Exposure in an enclosed area may be very harmful. Contact may irritate or burn skin and eyes. Fire may produce irritating and/or toxic gases. Runoff from fire control or dilution water may cause environmental contamination. Some of these materials may burn, but none ignite readily. Most vapors are heavier than air.
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 with SCBA required in confined spaces or high vapor concentrations; chemical-resistant suit and gloves
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 160 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.