UN 1163 — Dimethylhydrazine, unsymmetrical
Placard: Toxic. ERG Guide 131. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1163 is Dimethylhydrazine, unsymmetrical, a highly toxic and flammable hydrazine derivative assigned to ERG Guide 131. It is associated with rocket-fuel use and can be absorbed through skin as well as inhaled.
Hazard overview: UN 1163 presents severe toxic, skin-absorption and flammable vapor hazards. Vapors may form explosive mixtures with air, and exposure can cause serious systemic injury; responders should not treat it as an ordinary flammable liquid.
Response guidance: For a UN 1163 incident, responders should confirm the product using shipping papers, container markings, SDS and ERG Guide 131. Establish incident command, isolate the area, stay upwind and uphill, remove ignition sources when safe, keep vapors or runoff out of sewers and use compatible Class B fire-control agents from a protected position.
Firefighter training notes: Training for UN 1163 should emphasize combined toxicity, skin absorption, flammable vapor behavior, air monitoring and decontamination. Common errors include treating the incident only as a fire, entering vapor areas without SCBA, allowing sewer entry and failing to control ignition sources. Use ERG 131, SDS and incident command.
Regulatory context: Dimethylhydrazine, unsymmetrical is regulated as a hazardous material and may have additional occupational exposure, environmental and waste controls because of toxicity as well as flammability. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Dimethylhydrazine, unsymmetrical should be stored in tightly closed compatible containers in a cool, dry, well-ventilated flammable-liquid area with exposure controls, secondary containment and drain protection. Keep away from heat, ignition sources, oxidizers and incompatible materials.
UN 1163 Quick Details
Common Hazards of UN 1163
- TOXIC and FLAMMABLE; may be fatal if inhaled, ingested or absorbed through skin.
- Vapors may form explosive mixtures with air and travel to an ignition source.
- Liquid and vapor may irritate or burn skin, eyes and respiratory tissue.
- Vapors are heavier than air and may collect in low, confined or sewer areas.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or spill control may cause environmental contamination.
- Containers may rupture or explode when heated.
- Hydrazine derivatives may be highly toxic and may present serious systemic health hazards after skin or vapor exposure.
Chemical Identity & Physical Properties
Colorless to pale yellow fuming liquid with a fishy ammonia-like odor. Highly flammable and hygroscopic.
| Also known as | UDMH1,1-DimethylhydrazineDimazineHydrazine, 1,1-dimethyl-N,N-Dimethylhydrazine |
| CAS Number | 57-14-7 |
| Appearance | Colorless to pale yellow fuming liquid with a fishy ammonia-like odor. Highly flammable and hygroscopic. |
| Flash Point | -15C (5F) |
| Boiling Point | 63C (145F) |
| Vapor Density | 2.1 (heavier than air) |
| Water Reactivity | Soluble in water; no violent reaction but forms toxic solution |
Fireground Response Guidance — UN 1163
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fire or confined-space exposure. Chemical-resistant gloves, boots, splash protection and protective clothing should be selected using SDS, monitoring results and incident command because inhalation and skin absorption can be serious.
Isolation & Evacuation
First Actions for a UN 1163 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.
- Eliminate ignition sources if it is safe to do so.
- Do not touch or walk through spilled liquid unless properly trained and wearing appropriate protective equipment.
- Avoid breathing vapors and avoid skin or eye contact with liquid.
- Ventilate closed spaces before entering, but only if properly trained, equipped and authorized by incident command.
- Isolate the spill or leak area for at least 50 meters (150 feet) in all directions.
- For large spills, fire involvement or strong vapor movement, expand isolation and consider downwind evacuation based on monitoring and incident command.
- Use ERG Guide 131, shipping papers, SDS and local SOP for protective actions and entry decisions.
📋 Copy & Share Field Card
UN 1163 — Dimethylhydrazine, unsymmetricalUse 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.