UN 1066 — Nitrogen, compressed
Placard: Non-Flammable Gas. ERG Guide 120. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Nitrogen, compressed, is a non-flammable gas that is widely used in industrial settings, with a DOT class of 2, and is commonly encountered by first responders in transportation accidents and industrial settings, the scale of production and transport of this substance is massive, with millions of tons being moved every year, and its industrial uses include food processing, pharmaceuticals, and laboratory research, making it a critical component of modern life, however, its potential for asphyxiation and frostbite make it a significant hazard, and first responders must be trained to handle it properly, the correct handling and response to nitrogen, compressed, are crucial to preventing accidents and minimizing damage, and first responders must be aware of the potential hazards and take necessary precautions, the substance is highly volatile and can displace oxygen, leading to asphyxiation, and its vapors can cause frostbite if they come into contact with skin
Hazard overview: Nitrogen, compressed, is a non-flammable gas that can cause asphyxiation and frostbite, its vapors are initially heavier than air and can spread along the ground, collecting in low-lying areas, the substance can displace oxygen, leading to asphyxiation, and its vapors can cause frostbite if they come into contact with skin, the LC50 for nitrogen, compressed, is not well established, however, the substance is known to be highly hazardous, and first responders must exercise extreme caution when handling it, in the worst-case scenario, a large release of nitrogen, compressed, could result in a significant asphyxiation hazard, causing loss of life, and first responders must be prepared to respond quickly and effectively to minimize the damage, the substance can also cause containers to explode when heated, making it a significant threat to people and the environment
Response guidance: In the event of a spill or leak of nitrogen, compressed, first responders should ventilate the area and monitor oxygen levels, evacuating the area if oxygen levels fall below 19.5%, the correct suppression agent for this substance is not applicable, as it is non-flammable, however, inert gas can be used to displace oxygen and extinguish fires, CHEMTREC should be contacted immediately for assistance, and first responders should be aware of the potential for the substance to displace oxygen, leading to asphyxiation, and take necessary precautions, the isolation distance for small releases is not applicable, however, first responders should exercise caution when approaching the scene, as the substance can be highly volatile and cause asphyxiation
Firefighter training notes: First responders should be trained to respond to spills or leaks of nitrogen, compressed, with caution and awareness of the potential hazards, a common tactical error is underestimating the potential for asphyxiation, and first responders should be aware of the potential for the substance to displace oxygen, leading to asphyxiation, the ICS position needs to be aware of the potential hazards and take necessary precautions, and mutual aid criteria should be established to ensure a rapid and effective response, first responders should also be trained to use the correct PPE and suppression agents, and to follow established protocols for responding to spills or leaks of the substance
Regulatory context: Nitrogen, compressed, has a DOT class of 2, and is subject to regulations regarding transportation and storage, the OSHA PEL for this substance is not well established, however, the substance is known to be highly hazardous, and first responders must exercise extreme caution when handling it, the substance is also subject to regulations regarding its use and handling, and first responders should be aware of the potential hazards and take necessary precautions
Storage & handling: Nitrogen, compressed, should be stored in a well-ventilated area, away from heat sources and ignition sources, the substance should be stored in a container that is specifically designed for the storage of compressed gases, and the container should be labeled with the correct hazard warnings, the substance should also be stored at a temperature below its critical temperature, and the area should be equipped with a ventilation system, the top 3 incompatible materials for this substance are heat sources, ignition sources, and oxidizing agents, and the substance should be stored away from these materials to prevent accidents
UN 1066 Quick Details
Common Hazards of UN 1066
- Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite.
- Non-flammable gases.
- Containers may explode when heated.
- Ruptured cylinders may rocket.
Chemical Identity & Physical Properties
Nitrogen, compressed, is a colorless, odorless, and tasteless gas at room temperature, it has a boiling point of -196°C (-321°F) at atmospheric pressure, and a vapor density of 0.97, which is slightly lighter than air, the substance is also highly volatile, with a vapor pressure that can cause it to rapidly expand and spread, making it a significant hazard
| Also known as | N2Nitrogen gasCompressed nitrogenDinitrogenLiquid nitrogen (when cryogenic) |
| CAS Number | 7727-37-9 |
| Appearance | Colorless, odorless, tasteless gas at room temperature. Non-flammable and chemically inert under normal conditions. |
| Flash Point | Not applicable (non-flammable gas) |
| Boiling Point | -196C (-321F) at atmospheric pressure |
| Vapor Density | 0.97 (slightly lighter than air as gas, but vapors from liquefied nitrogen are initially heavier than air) |
| Water Reactivity | No reaction with water; chemically inert |
Fireground Response Guidance — UN 1066
Extinguishing Media
PPE Requirements
The minimum PPE level required for responding to a spill or leak of nitrogen, compressed, is Level D, with insulated gloves and a face shield required when handling liquefied or cryogenic nitrogen to prevent frostbite, an SCBA is required in oxygen-deficient atmospheres, and first responders should use caution when handling the substance, the correct PPE is crucial to preventing injury and illness, and first responders should be aware of the potential hazards and take necessary precautions, the PPE should include insulated gloves and a face shield to prevent frostbite, and a self-contained breathing apparatus (SCBA) to prevent inhalation of the substance
Isolation & Evacuation
First Actions for a UN 1066 Incident
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- Consider initial downwind evacuation for at least 100 meters (330 feet).
📋 Copy & Share Field Card
UN 1066 — Nitrogen, 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.