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Hazard class 2.1

Class 2.1: Flammable gas

Gases that ignite easily in air — for example propane and butane. Below is every Class 2.1 entry in 49 CFR §172.101 that has a UN/NA number — 79 entries.

IDProper shipping nameClassPG
UN1001Acetylene, dissolved2.1—
UN1010Butadienes, stabilized or Butadienes and Hydrocarbon mixture, stabilized containing more than 40% butadienes2.1—
UN1011Butane see also Petroleum gases, liquefied2.1—
UN1012Butylene see also Petroleum gases, liquefied2.1—
UN1027Cyclopropane2.1—
UN10301,1-Difluoroethane or Refrigerant gas R 152a2.1—
UN1032Dimethylamine, anhydrous2.1—
UN1033Dimethyl ether2.1—
UN1035Ethane2.1—
UN1036Ethylamine2.1—
UN1037Ethyl chloride2.1—
UN1038Ethylene, refrigerated liquid (cryogenic liquid)2.1—
UN1039Ethyl methyl ether2.1—
UN1041Ethylene oxide and carbon dioxide mixtures with more than 9 percent but not more than 87 percent ethylene oxide2.1—
UN1049Hydrogen, compressed2.1—
UN1055Isobutylene see also Petroleum gases, liquefied2.1—
UN1057Lighters containing flammable gas2.1—
UN1057Lighter refills containing flammable gas not exceeding 4 fluid ounces (7.22 cubic inches) and 65 grams of flammable gas2.1—
UN1060Methyl acetylene and propadiene mixtures, stabilized2.1—
UN1061Methylamine, anhydrous2.1—
UN1063Methyl chloride or Refrigerant gas R 402.1—
UN1075Petroleum gases, liquefied or Liquefied petroleum gas2.1—
UN1077Propylene see also Petroleum gases, liquefied2.1—
UN1081Tetrafluoroethylene, stabilized2.1—
UN1083Trimethylamine, anhydrous2.1—
UN1085Vinyl bromide, stabilized2.1—
UN1086Vinyl chloride, stabilized2.1—
UN1087Vinyl methyl ether, stabilized2.1—
UN1860Vinyl fluoride, stabilized2.1—
NA1911Diborane mixtures2.1—
UN1912Methyl chloride and methylene chloride mixtures2.1—
UN1950Aerosols, flammable, (each not exceeding 1 L capacity)2.1—
UN1950Aerosols, flammable, n.o.s. (engine starting fluid) (each not exceeding 1 L capacity)2.1—
NA1954Refrigerant gases, n.o.s. or Dispersant gases, n.o.s.2.1—
UN1954Compressed gas, flammable, n.o.s.2.1—
UN1957Deuterium, compressed2.1—
UN19591,1-Difluoroethylene or Refrigerant gas R 1132a2.1—
NA1961Ethane-Propane mixture, refrigerated liquid2.1—
UN1961Ethane, refrigerated liquid2.1—
UN1962Ethylene2.1—
UN1964Hydrocarbon gas mixture, compressed, n.o.s.2.1—
UN1965Hydrocarbon gas mixture, liquefied, n.o.s.2.1—
UN1966Hydrogen, refrigerated liquid (cryogenic liquid)2.1—
UN1969Isobutane see also Petroleum gases, liquefied2.1—
UN1971Methane, compressed or Natural gas, compressed (with high methane content)2.1—
UN1972Methane, refrigerated liquid (cryogenic liquid) or Natural gas, refrigerated liquid (cryogenic liquid, with high methane content)2.1—
UN1978Propane, see also Petroleum gases, liquefied2.1—
UN2034Hydrogen and Methane mixtures, compressed2.1—
UN20351,1,1-Trifluoroethane or Refrigerant gas, R 143a2.1—
UN2037Gas cartridges, (flammable) without a release device, non-refillable2.1—
UN2037Receptacles, small, containing gas or gas cartridges (flammable) without release device, not refillable and not exceeding 1 L capacity2.1—
UN20442,2-Dimethylpropane2.1—
UN2200Propadiene, stabilized2.1—
UN2203Silane2.1—
UN2419Bromotrifluoroethylene2.1—
UN2452Ethylacetylene, stabilized2.1—
UN2453Ethyl fluoride or Refrigerant gas R1612.1—
UN2454Methyl fluoride, or Refrigerant gas R 412.1—
UN25171-Chloro-1,1-difluoroethane or Refrigerant gas R 142b2.1—
UN2601Cyclobutane2.1—
UN3138Ethylene, acetylene and propylene in mixture, refrigerated liquid with at least 71.5 percent ethylene with not more than 22.5 percent acetylene and not more than 6 percent propylene2.1—
UN3150Devices, small, hydrocarbon gas powered or Hydrocarbon gas refills for small devices with release device2.1—
UN3153Perfluoro(methyl vinyl ether)2.1—
UN3154Perfluoro(ethyl vinyl ether)2.1—
UN3161Liquefied gas, flammable, n.o.s.2.1—
UN3167Gas sample, non-pressurized, flammable, n.o.s., not refrigerated liquid2.1—
UN3252Difluoromethane or Refrigerant gas R 322.1—
UN3312Gas, refrigerated liquid, flammable, n.o.s. (cryogenic liquid)2.1—
UN3354Insecticide gases, flammable, n.o.s.2.1—
UN3358Refrigerating machines, containing flammable, non-toxic, liquefied gas2.1—
UN3468Hydrogen in a metal hydride storage system or Hydrogen in a metal hydride storage system contained in equipment or Hydrogen in a metal hydride storage system packed with equipment2.1—
UN3478Fuel cell cartridges or Fuel cell cartridges contained in equipment or Fuel cell cartridges packed with equipment, containing liquefied flammable gas2.1—
UN3479Fuel cell cartridges or Fuel cell cartridges contained in equipment or Fuel cell cartridges packed with equipment, containing hydrogen in metal hydride2.1—
UN3501Chemical under pressure, flammable, n.o.s2.1—
UN3504Chemical under pressure, flammable, toxic, n.o.s2.1—
UN3505Chemical under pressure, flammable, corrosive, n.o.s2.1—
UN3510Adsorbed gas, flammable, n.o.s2.1—
UN3529Engine, internal combustion, flammable gas powered or Engine, fuel cell, flammable gas powered or Machinery, internal combustion, flammable gas powered or Machinery, fuel cell, flammable gas powered2.1—
UN3537Articles containing flammable gas, n.o.s.2.1—
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Other hazard classes

Class 1Class 2.2Class 2.3Class 3Class 4.1Class 4.2Class 4.3Class 5.1Class 5.2Class 6.1Class 6.2Class 7Class 8Class 9
Source: 49 CFR §172.101 via eCFR.gov, current as of Oct 23, 2026. Reference only.