This information replaces the information on shipping canister stove fuel found on pages 37 and 49 of the first edition of Long Distance Hiking.
Canister Fuels like butane, isobutane, and propane, are all fuels are characterized by the US Postal Service (USPS) as class 2 flammable gases. Hikers may ship up to 33.8oz (1L) of canister fuel in metal receptacles when properly packaged using the USPS Packaging Instruction 2A from USPS Publication 52. Canister fuel cannot be shipped via air or international mail and must be shipped using Parcel Select, Standard Mail, or Standard Post.
Not sure whether your fuel can be shipped by USPS? Refer to USPS Publication 52, Appendix A.