Radioactive materials are prohibited in international mail and domestic mail if required to bear the DOT Radioactive White–I, Radioactive Yellow–II, Radioactive Yellow–III label, or the Fissile label (49 CFR 172.436, 172.438, or 172.440, respectively) or if it contains quantities of radioactive material in excess of those authorized in 347. Radioactive materials are prohibited in domestic mail via air transportation. For international mail, the standards in IMM 135.5 apply.
The only categories of radioactive material that are mailable are those that can be classified as a “limited quantity” under 49 CFR and that meet the limits in Exhibit 347.22: excepted instruments, articles, and devices, and excepted articles containing natural uranium and thorium. Accurate documentation of the activity limits, which must not exceed those specified in Exhibit 347.22, must be provided.
Separate packaging requirements apply as follows.