The United States Postal Service has banned the international shipment of tablets, smartphones and other devices that contain lithium ion, lithium alloy and rechargeable batteries. The ban goes into effect starting May 16.

Lithium batteries, which power many personal electronic devices, can explode or catch fire in certain conditions, said Fast Company in a recent report on the ban. In order to get around this, consumer electronic manufacturers such as Apple or Amazon ship their products with a minimal charge--which mitigates the safety risk. The Fast Company report also points out that lithium batteries have been implicated in at least two fatal cargo plane crashes since 2006.

While the news is unfortunate for those looking to run an errand for a friend overseas or send a gadget internationally at an affordable price, it's even more unfortunate for US troops abroad. The battery ban extends to shipping to army and diplomatic post offices abroad, making it extremely difficult to get gadgets to troops posted at international bases.

Those that wish to send gadgets internationally will be forced to use private shipping companies such as DHL, UPS, FedEx and others. The price is typically higher with such carriers, though, which may be enough to deter people from sending gadgets altogether.

Despite the upcoming ban, there is some good news for USPS shippers. The Postal Service anticipates that by January 1 of next year, custeromers will be able to mail items with lithium batteries so long as they declare them.

For now, if you want to send a gadget through the post office, you'd better ship it soon.