If dry ice is used as a refrigerant, it must be placed outside the secondary packaging. Interior supports must be provided to secure the secondary packaging in the original position after the dry ice has dissipated. The packaging must be designed and constructed to permit the release of carbon dioxide gas to prevent a buildup of pressure that could rupture the packaging.

A "miscellaneous hazardous materials" label (class 9) must be affixed to the outer package along with a "dry ice" label that includes the UN designation "UN 1845."

The net quantity (weight) of the dry ice must also be stated. If the package (category B or exempt substance) is sent through the mail, the amount of dry ice that can be used is limited to 5 pounds, unless advanced arrangements have been made.