IATA Dangerous Goods classes
The International Air Transport Association (IATA) groups substances and articles that pose an in-flight safety hazard into 9 classes (some with sub-divisions). Each class determines whether an item can travel in carry-on, in checked baggage, or only as cargo — and the packaging, labelling and quantity limits that apply. These rules apply on top of ordinary customs rules.
- Class 1ExplosivesCARRY-ON NOCHECKED NOCARGO ONLY
Substances and articles with explosive, pyrotechnic or fire-hazard properties (Divisions 1.1-1.6). Ammunition falls in Division 1.4S under packaging-restricted conditions.
Fireworks · Sporting ammunition (Division 1.4S, cargo-only with specific packaging) · Blasting caps +1
- Class 2.1Flammable gasCARRY-ON NOCHECKED NOCARGO ONLY
Gases that are flammable in air at 20 °C and 101.3 kPa. Includes butane lighters, camping gas canisters, aerosol cans with propellant, and refillable gas cartridges.
Camping butane canisters (all sizes) · Spare butane lighter refills · Aerosol paint cans +1
- Class 2.2Non-flammable, non-toxic gasCARRY-ON NOCHECKED NOCARGO ONLY
Compressed non-flammable, non-toxic gases (oxygen, nitrogen, refrigerants, dive cylinders). Portable oxygen concentrators (POCs) face device-specific carry-on allowances with airline approval.
Scuba dive tanks · Camping-stove compressed-gas cylinders · Medical oxygen cylinders (except approved POCs) +1
- Class 3Flammable liquidsCARRY-ON OKCHECKED OK
Liquids with flash point ≤ 60 °C. Covers alcoholic beverages above 70% ABV, perfumes and colognes above 70% alcohol, and most solvent-based paints. Alcoholic beverages 24-70% ABV treated as personal goods (5 L per passenger limit).
Alcoholic beverages 24-70% ABV (whisky, vodka, gin, rum) · Perfume and cologne · Nail polish and remover +2
- Class 4Flammable solids, spontaneously combustible, and dangerous-when-wet substancesCARRY-ON NOCHECKED NOCARGO ONLY
Division 4.1 flammable solids ignite by friction or heat (matches, sulfur, magnesium, solid fuel for camping stoves, naphthalene mothballs, nitrocellulose tablets); Division 4.2 spontaneously combustible substances ignite when exposed to air at normal temperatures (oily rags, white phosphorus, certain catalysts, some metal alloys); Division 4.3 substances dangerous when wet emit flammable gases or ignite on contact with water (calcium carbide, alkali metals, alkaline-earth alloys). Class 4 is the second most-restricted hazmat class for passenger air transport behind Class 1 explosives, with most divisions forbidden in passenger baggage of any kind. Container damage and accidental water exposure are the principal risks.
Safety matches (one book permitted on-person only) · Strike-anywhere matches (prohibited) · Solid fuel tablets for camping stoves +1
- Class 5Oxidising substances and organic peroxidesCARRY-ON NOCHECKED NOCARGO ONLY
Division 5.1 oxidising substances (hydrogen peroxide ≥ 8%, pool-cleaning chlorine, nitrates), 5.2 organic peroxides.
Pool-shock / high-strength chlorine · Hair-bleach peroxide > 12% · Ammonium nitrate fertiliser
- Class 6Toxic and infectious substancesCARRY-ON NOCHECKED NOCARGO ONLY
Division 6.1 toxic substances cause death, injury, or harm to human health if swallowed, inhaled, or absorbed through skin (pesticides, cyanides, arsenic compounds, some chemotherapy reagents, mercury compounds, organic peroxides at certain concentrations). Division 6.2 infectious substances contain or are reasonably expected to contain pathogens — Category A is biological material capable of causing permanent disability, life-threatening or fatal disease in humans or animals (Ebola, smallpox, anthrax cultures), Category B is biological material with lower risk (most diagnostic specimens, blood for serology). Class 6 carriage rules are uniformly tight in passenger baggage; medical-isotope shipments and clinical-trial specimens dominate the cargo side under specialised packaging requirements.
Concentrated pesticides · Mercury thermometers (historical; phased out under UN Minamata Convention) · Laboratory biological specimens
- Class 7Radioactive materialCARRY-ON NOCHECKED NOCARGO ONLY
Material containing radionuclides above activity concentration limits. Includes industrial radiography sources, medical isotopes, some smoke-detector americium sources below exempt limits (allowed).
Industrial radiography sources · Medical isotopes · Uranium or thorium samples for mineral collectors (prohibited)
- Class 8Corrosive substancesCARRY-ON NOCHECKED NOCARGO ONLY
Liquids or solids that destroy living tissue or damage materials. Lead-acid and wet-cell batteries fall here; sealed lithium batteries are Class 9.
Car / motorcycle wet-cell batteries · Drain-cleaner liquids · Laboratory acids and alkalis
- Class 9Miscellaneous dangerous goodsCARRY-ON OKCHECKED OK
Substances and articles presenting a hazard during transport not covered by other classes. Lithium-ion and lithium-metal batteries are the most common subcategory for passenger travel (UN3480 / UN3090 when shipped alone; UN3481 / UN3091 when packed with or contained in equipment).
Lithium-ion batteries ≤ 100 Wh (in or with equipment) · Spare lithium batteries (carry-on only, not checked) · Power banks +3