It is very important for a parcel shipper to know and follow the rules of the transportation service providers used by the shipper however named, e.g., tariffs, service guides, or terms and conditions. This knowledge should be acquired before shipping, not after a penalty has been incurred or other negative consequences occur.

In this installment PARCEL Counsel, we will focus on the rules of the USPS and, in particular, what the USPS calls “Prohibitions and Restrictions.” There are two sets of these. One relates to shipping packages domestically within the United States ( and the other relates to international shipments (

Within both of these sets of rules, certain items are designated as “prohibited” and others as “restricted.” Prohibited items may not be sent in domestic United States mail. These are airbags, ammunition, explosives, gasoline, and marijuana.

Internationally prohibited items may not be sent from the United States to any country. These items include the prohibited items for domestic mailing plus aerosols, alcoholic beverages, cigarettes, dry ice, hemp-based products, nail polish, perfumes, and poisons.

Just as there are items prohibited for domestic or international shipments, there are also items that are restricted. These items may be sent, but only if the shipper follows all of the rules relating to a particular item. A complete list may be found at the USPS website at the links listed above.

The rules relating to prohibited items are pretty easy to follow — if an item is on the list, you cannot ship it. The rules relating to restricted items are not as simple. They include items that are commonly found in the home and office. For instance, hand sanitizers may be mailed domestically subject to restrictions, but would be prohibited to mail internationally. Furthermore, they might be considered to be hazardous materials (Hazmat) and subject to further rules: USPS Publication 52, Hazardous, Restricted, & Perishable Mail.

It is important to note that the restrictions for mailing items are not the same for different items. They vary from item to item. Restrictions on the same item can also vary depending on whether it is being mailed domestically or internationally. As an example, here are the restrictions for lithium batteries as they appear on the USPS website for domestic shipments:

“Lithium Batteries

For domestic mailings only, small consumer-type primary lithium cells or batteries (lithium metal or lithium alloy) like those used to power cameras and flashlights are mailable domestically under certain conditions.

Lithium Batteries in Electronic Devices

If you're mailing pre-owned, damaged, or defective electronic devices containing or packaged with lithium batteries, you must send them via ground transportation; they are prohibited in air transportation.

These devices must be marked on the outer packaging with the text, "Restricted Electronic Device" and "Surface Transportation Only."

Shipping Lithium Batteries”

The international restrictions for mailing lithium batteries are as follows:

“Lithium Batteries

Only lithium cells and batteries that are properly installed in the equipment they are intended to operate may be mailed internationally or to APO/FPO/DPO locations if the destination country and APO/FPO/DPO permit their receipt.

Prohibited Lithium Battery Shipments

Lithium batteries packed with, but not installed in, equipment

Lithium batteries sent separately from equipment

Damaged or recalled batteries

All pre-owned, damaged, or defective electronic devices containing or packaged with lithium batteries”

To conclude, the first very critical step is to thoroughly research the USPS website to determine if the items shipped via USPS are restricted, prohibited or hazardous… and then go from there. All for now!

Brent Wm. Primus, J.D., is the CEO of Primus Law Office, P.A. and the Senior Editor of transportlawtexts, inc. Previous columns, including those of William J. Augello, may be found in the “Content Library” on Your questions are welcome at

This article originally appeared in the September/October, 2022 issue of PARCEL.