Nitrous oxide, refrigerated liquid
HMT 15 June 2026
Reference only — HMT snapshot for inspection and audit support; not a shipping paper, placard mandate, or CVI record.
Use Print / PDF below for field notes.
- UN / ID
- UN 2201
- Hazard class
- 2.2
- Packing group
- —
- ERG guide
- ERG 122
- Special provisions
- SP B6, SP T75, SP TP5, SP TP22
- Source
- 49 CFR §172 (15 June 2026)
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Nitrous oxide, refrigerated liquid
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas or nitrous, among others, is a chemical compound, an oxide of nitrogen with the formula N2O. At room temperature, it is a colourless non-flammable gas, and has a slightly sweet scent and flavour. At elevated temperatures, nitrous oxide is a powerful oxidiser similar to molecular oxygen. Nitrous oxide has significant medical uses, especially in surgery and dentistry, for its anaesthetic and pain-reducing effects, and it is on the World Health Organization's List of Essential Medicines Wikipedia
Substance Data
Source:
PubChem (HSDB, 14.12.2019)
CAS-Number10024-97-2 |
Flash Point— | Boiling Point— |
Hazardous Materials Table
Source:
49 CFR §172 (15 June 2026)
(3) Hazard class 2.2
Non-toxic, non-flammable gases |
UN 2201 |
— |
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×Note:Special provisions may be very complex. The extracts are taken from 49 CFR §172.102. Please be careful with the information, as necessary, additional conditions may be applied that are not written here. Please check the original source and report bugs. | B6 | |
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| T75 | When portable tank instruction T75 is referenced in Column (7) of the § 172.101 Table, the applicable refrigerated liquefied gases are authorized to be transported in portable tanks in accordance with the requirements of § 178.277 of this subchapter. Browse special provision T75 |
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| TP5 | For a portable tank used for the transport of flammable refrigerated liquefied gases or refrigerated liquefied oxygen, the maximum rate at which the portable tank may be filled must not exceed the liquid flow capacity of the primary pressure relief system rated at a pressure not exceeding 120 percent of the portable tank's design pressure. For portable tanks used for the transport of refrigerated liquefied helium and refrigerated liquefied atmospheric gas (except oxygen), the maximum rate at which the tank is filled must not exceed the liquid flow capacity of the pressure relief device rated at 130 percent of the portable tank's design pressure. Except for a portable tank containing refrigerated liquefied helium, a portable tank shall have an outage of at least two percent below the inlet of the pressure relief device or pressure control valve, under conditions of incipient opening, with the portable tank in a level attitude. No outage is required for helium. Browse special provision TP5 |
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| TP22 | |
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| (9A) Passenger aircraft/rail | Forbidden |
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| (9B) Cargo aircraft only | Forbidden |
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| (10A) Location | D Stowage category “D” means the material must be stowed “on deck only” on a cargo vessel or on a passenger vessel carrying a number of passengers limited to not more than the larger of 25 passengers or one passenger per each 3 m of overall vessel length, but the material is prohibited on a passenger vessel in which the limiting number of passengers is exceeded. Source: 49 CFR §172.101(k) |
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| (10B) Other | |
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Segregation chart for load, transport, and storage
This chart shows whether loading, transport, or storage with other hazard classes is permitted, prohibited, or restricted. Based on 49 CFR §177.848.
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Must not be loaded, transported, or stored together in the same vehicle or facility. |
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May be loaded, transported, or stored together. |
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May be loaded, transported, or stored together only with restrictions. |
