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Prohibited, Restricted, and Non-Mailable Items

Americans across the United States use the U.S. Mail daily and rely upon the Postal Service to ship numerous types of items for personal and business purposes. However, what people may not know is that certain items and substances should never enter the mail system. These materials are not only considered hazardous but are also illegal to send through the mail. Prohibited, restricted, and non-mailable items include anything containing liquid mercury, fireworks, live ammunition, strike-anywhere matches, explosive or flammable devices, and corrosive or acidic substances and materials, as well as several others.



Small arms ammunition is categorized as explosive materials by the U.S. Department of Transportation. Ammunition that is designed to be fired from a pistol, revolver, rifle, or shotgun, as well as associated primers and blank cartridges (including those designed for tools) and propellant powder for use in any firearm, is prohibited from mailing. Under federal law, it is illegal to send these types of ammunition, domestically or internationally, via the U.S. Mail. Small arms ammunition poses a significant danger to Postal employees, equipment, and customers, and you could be subject to civil penalties and criminal charges, if you send them through USPS.



The shipment of firearms through the U.S. Mail is highly regulated by the Gun Control Act of 1968 and USPS Publication 52, Hazardous, Restricted and Perishable Mail.

The Postal Inspection Service is regularly engaged with our federal, state and local partners to thwart any loss associated to firearms, stop any illicit of firearms trafficking through the mail and ensure the safety of our infrastructure, employees and customers.


These brilliant celebratory displays of color and design are beautiful to behold in the sky when handled legally and properly. However, they are illegal to ship through the United States Postal Service (USPS). Illegal shipments of fireworks pose a significant hazard while in air transportation and endanger the lives of Postal employees and the traveling public.



Liquid mercury on its own or contained in various items is prohibited in the mail. Liquid mercury is a hazardous substance that produces toxic vapors if exposed to air and causes mercury poisoning if the vapors become inhaled. Older styled thermometers, blood pressure gauges, and barometers — which often contain liquid mercury– may become damaged or broken during the shipping process. The threat of serious illness or injury caused by exposure to a leaking mercury package is never worth shipping the item.



Other items that appear safe because they are used during everyday activities around the house also pose a significant risk during transportation and are considered hazardous materials. Some common items that you might not think of include flammable aerosol products (spray disinfectants, spray paints, and hairspray), lithium batteries, safety matches, perfume, and cosmetic products such as nail polish and nail polish remover. Although some of these materials are allowed to travel through the mail, there are strict quantity limits, packaging, and marking requirements. Additionally, some items are not allowable in airmail but may be sent with ground delivery only.



Lithium batteries power numerous electronics from cell phones, laptops, and tablets to wireless headphones, toys, and portable tools. What is not generally known is that these batteries are considered hazardous materials and remain highly regulated in transportation. When improperly prepared and shipped, packages containing lithium batteries are prone to catch fire and possibly explode during handling. When correctly prepared, declared, and shipped in quantities below the USPS threshold, these risks can be reduced and avoided. It is important to note that larger lithium batteries such as those needed for e-bikes, scooters, and electric cars are prohibited from being mailed at all.


When using a Post Office to ship a package, Postal employees will ask if the package contains perfume, aerosols, lithium batteries, mercury and other hazardous materials. Sometimes people incorrectly assume the items included are not hazardous when they are. Others purposely say the item is not present, even though they know it is, just so they can ship the package. Either way, the outcome of shipping these dangerous items can have very dangerous or fatal consequences. If an incident occurs in which improperly prepared or undeclared items have been intercepted or encountered, legal consequences including criminal charges and/or civil penalties may be sought against the shipper and/or recipient of the package.


If you have any questions regarding what is acceptable to ship through the mail, please consult with your local Post Office before you mail potentially hazardous items. The simple act of asking a question could help prevent damage to USPS facilities and injuries to Postal employees. 


To learn more about the USPS guidelines on hazardous, prohibited, and restricted mailings visit:


Think it's OK to mail ammunition? Watch this video before you head to the Post Office.

Ammunition Transcript
Munición Activa

¿Piensas que está bien enviar munición activa a través del correo? Ve este video antes de ir a la Oficina Postal.


Think sending fireworks through the mail is legal? Think again…It's definitely not!

Lithium Batteries

Does that cool tech gift you plan on sending contain a lithium battery? Is it OK to send? Before you head to the Post Office, check out this video.


Is that antique thermometer or barometer safe to mail? Before you head to the Post Office, check out this video.

Protect Yourself


    Learn more about the hazardous, non-mailable, prohibited, and restrictive material by reading the United States Postal Service’s Publication 52 – Hazardous, Restricted, and Perishable Mail, which can be found HERE


    When shipping a package, be honest about the contents. A Postal employee will name a list of specific hazardous items. If one of your items is on the list, let the employee know. 


    If in doubt, don’t mail an item without checking with your local Post Office™ location.


To protect yourself and others from consumer frauds, visit our fraud prevention page.

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