743 Perishable Matter with Dry Ice

Mailpieces containing mailable matter packed in dry ice (carbon dioxide solid) must meet all requirements in 349 that apply to sending dry ice in domestic mail via air transportation (refer to Packaging Instruction 9A in Appendix C). For air transportation, the amount of dry ice cannot exceed 5 pounds per mailpiece. Dry ice is prohibited to be mailed to international, APO/FPO/ DPO or domestic territories outside the customs territory of the United States (refer to 612).