UN 1928 — Methyl magnesium bromide in ethyl ether
Placard: Dangerous When Wet. ERG Guide 138. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1928 is Methyl magnesium bromide in ethyl ether, a dangerous-when-wet Grignard reagent in ethyl ether assigned to ERG Guide 138. It can react violently with water and release flammable methane while the ether solvent creates major vapor fire risk.
Hazard overview: UN 1928 presents dangerous-when-wet reaction, methane generation, ether vapor flashback, spontaneous ignition and container explosion hazards. Do not use water, foam or CO2 directly.
Response guidance: For a UN 1928 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 138. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff or vapor spread and choose entry/fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1928 should emphasize dangerous-when-wet behavior, flammable gas generation, dry-agent/Class D selection, re-ignition and ignition control. Use ERG 138, SDS and local SOP.
Regulatory context: Methyl magnesium bromide in ethyl ether is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by formulation, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Methyl magnesium bromide in ethyl ether should be stored dry in compatible sealed containers away from water, moisture, oxidizers, acids where incompatible, ignition sources and unauthorized access. Keep compatible dry extinguishing media available.
UN 1928 Quick Details
Common Hazards of UN 1928
- DANGEROUS WHEN WET and highly flammable ether solution; contact with water can cause violent reaction.
- Reacts with water or moist air to release heat and flammable methane gas.
- Ethyl ether solvent vapors are extremely flammable and can flash back.
- May ignite spontaneously if moisture, air exposure or ignition sources are present.
- Vapor explosion hazard exists in low areas, drains and confined spaces.
- Do not use water, foam or CO2 directly on the material unless specialist guidance confirms compatibility.
- Containers may rupture or explode when heated.
Chemical Identity & Physical Properties
Clear to pale yellow liquid solution in ethyl ether. Characteristic ether odor. Highly reactive organometallic compound.
| Also known as | Methylmagnesium bromideBromomethylmagnesiumGrignard reagentMeMgBr in ether |
| CAS Number | 75-16-1 |
| Appearance | Clear to pale yellow liquid solution in ethyl ether. Characteristic ether odor. Highly reactive organometallic compound. |
| Flash Point | -45C (-49F) (ethyl ether solvent) |
| Boiling Point | 35C (95F) (ethyl ether solvent) |
| Vapor Density | 2.6 (heavier than air) |
| Water Reactivity | Reacts violently with water producing flammable methane gas and heat. May ignite spontaneously. |
Fireground Response Guidance — UN 1928
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for smoke, dust, sulfur dioxide/corrosive vapor or fire exposure. Wear chemical-resistant and fire-appropriate protection selected from SDS; avoid moisture contamination.
Isolation & Evacuation
First Actions for a UN 1928 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing vapors, fumes, dust, mist, smoke or gas and avoid skin or eye contact.
- Keep water, foam and moisture away from released product unless incident command confirms a compatible control use.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or leak area and expand the perimeter if vapor, dust, fire involvement, gas accumulation or unknown concentration is present.
- Use ERG Guide 138, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1928 — Methyl magnesium bromide in ethyl etherUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.