Carbon dioxide (CO2) and other nonflammable, nontoxic gases
Quantity limit: Up to four cartridges/cylinders containing nonflammable gas may be carried. Each cylinder must not exceed 50 ml (equivalent to 28 g carbon dioxide cartridge).
May be carried in carry-on or checked baggage.
Airline approval is required.
Cartridges/cylinders not installed in the device should be securely packed.
Compressed gas cylinders, canisters, and cartridges with a volume larger than 50 ml are forbidden in carry-on or checked baggage unless covered by another exception in this table.
Empty, non-pressurized cartridges/cylinders for nonflammable, nontoxic products are not restricted as hazardous materials and may be carried in carry-on or checked baggage.
TSA security rules may prohibit some devices and their cartridges/cylinders in carry-on baggage (air guns, etc.).