USPS® does not offer refrigeration services. You may ship frozen articles using packaging supplies like Dry Ice at your own risk and according to Publication 52 section on Dry Ice. The frozen product must be packaged so as not to leak or cause odors. You could be held liable for damage to other mail if yours is not properly packaged.
- Insurance may be purchased for perishable items. However, the claim will not be paid if the item is spoiled regardless of whether or not it arrived on time.
- Priority Mail® and Priority Mail Express® services are recommended for mailing items requiring refrigeration.
- Many restrictions apply to mailing produce to certain areas of the country (i.e., Florida, Hawaii, California). Please refer to the Department of Agriculture for current restrictions. Department of Agriculture phone numbers are listed in local telephone directories.
In what Mail Classes can I Ship Items in Dry Ice?
- Dry Ice is prohibited from International Mail.
- Dry ice is permitted in quantities of up to 5 pounds per mailpiece when shipped as Domestic Mail via air transportation (Priority Mail Express, Priority Mail®, and First-Class Mail®).
- Dry ice is permitted in quantities more than 5 pounds per mailpiece when shipped as Domestic Mail via surface transportation (Parcel Select®, USPS Marketing Mail™, and USPS Ground Advantage®).
How Shipments Containing Dry Ice Should Be Sent?
As mentioned above, your package should be sealed so as to not leak or cause odors. The container should be leak‐proof, but not air‐tight. It must be able to contain liquid condensation while it releases the carbon dioxide gas that is generated as the ice melts. If the container is air‐tight, the pressure can build until it ruptures or explodes.
In addition, good insulation is needed to ensure the effectiveness of the Dry Ice.
- An inexpensive Styrofoam cooler from the grocery store is not suggested:
- It breaks easily.
- It usually is not the right shape for shipping.
- A thicker poly styrene box, as seen below, is suggested:
- It reduces the amount of dry ice needed
- It allows extended shipping times
A combination package, shown below, is an option that addresses several concerns.
- The inner packaging will hold any condensation.
- The outer cardboard box is securely closed without being air‐tight.
- Through The Postal Store®, you can purchase the Priority Mail Express® Cold Chain Packaging. It consists of one Priority Mail Express® Box and one polystyrene cooler.
If you purchase a container specifically made to hold Dry Ice, it will come with closure instructions. To ensure safe transport, all parts of the packaging should be used according to the manufacturer's instructions.
Do Shipments with Dry Ice Need to be Marked and Documented?
- Each mailpiece must be clearly marked on the address side with:
- The name of the contents being cooled (such as frozen medical specimens, steaks)
- The net weight of the dry ice
- For air transportation, each mailpiece must:
- Bear a Class 9 DOT miscellaneous hazardous material warning label
- Be clearly marked "Carbon Dioxide Solid" or "Dry Ice"
- Have a properly completed shipper's declaration for dangerous goods prepared in triplicate and affixed to the outside of the mailpiece
- For surface transportation, each mailpiece must be clearly marked either:
- "Surface Only" or
- "Surface Mail Only" and "Carbon Dioxide Solid, UN1845" or
- "Dry Ice, UN1845"
