UN 1660 — Nitric oxide, compressed
Placard: Toxic Gas. ERG Guide 124. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1660 is Nitric oxide, compressed, a toxic hazardous material assigned to ERG Guide 124. Responders should verify the exact product with shipping papers, package markings and SDS before close action.
Hazard overview: UN 1660 presents toxic exposure hazards by inhalation, ingestion or skin contact. Fire, decomposition or runoff may produce toxic contamination and require air monitoring, isolation and decontamination.
Response guidance: For a UN 1660 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 124. Establish incident command, isolate the area, stay upwind, prevent dust or vapor exposure, control runoff and choose entry or cleanup actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1660 should emphasize toxic exposure routes, air monitoring, PPE selection, decontamination and preventing contaminated runoff. Use ERG 124, SDS and local SOP.
Regulatory context: Nitric oxide, compressed 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: Nitric oxide, compressed should be stored in tightly closed compatible containers in a secure toxic-material area according to SDS and local hazardous materials procedures.
UN 1660 Quick Details
Common Hazards of UN 1660
- TOXIC material; may be harmful or fatal if inhaled, ingested or absorbed through skin.
- Avoid breathing vapors, dust or mist and avoid skin or eye contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may carry toxic contamination and may pollute waterways.
- Containers may rupture or fail when heated.
- Specific toxicity and absorption risk should be confirmed from shipping papers and SDS.
Chemical Identity & Physical Properties
Colorless to brown gas (brown when exposed to air due to oxidation to nitrogen dioxide) with a sharp, sweet odor. Shipped as a compressed gas.
| Also known as | Nitrogen monoxideNitrogen oxideMononitrogen monoxideNO |
| CAS Number | 10102-43-9 |
| Appearance | Colorless to brown gas (brown when exposed to air due to oxidation to nitrogen dioxide) with a sharp, sweet odor. Shipped as a compressed gas. |
| Flash Point | Not applicable (non-flammable gas) |
| Boiling Point | -152C (-242F) |
| Vapor Density | 1.04 (slightly heavier than air) |
| Water Reactivity | No significant reaction with water, but oxidizes rapidly in air to form corrosive nitrogen dioxide |
Fireground Response Guidance — UN 1660
Extinguishing Media
PPE Requirements
Use protective equipment selected from SDS, monitoring results and incident command.
Isolation & Evacuation
First Actions for a UN 1660 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 or mist and avoid all skin or eye contact.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Avoid creating dust clouds or spreading contaminated liquid, powder, solution, runoff or debris.
- 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 dust, vapor, fire involvement or unknown concentration is present.
- Use ERG Guide 124, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1660 — Nitric oxide, compressedUse 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.