"We have received reports of detached blades involving a very small percentage of the adapters sold, but no injuries have been reported," the California company said on a Web page providing adapter exchange details.
The part Apple is offering to replace is an "Ultracompact USB power adapter" reportedly included with iPhone 3G models sold in Japan, Canada, Mexico, the United States and a half dozen South American countries.
"Customer safety is always Apple's top priority, and therefore we have voluntarily decided to exchange every Ultracompact power adapter for a new, redesigned adapter, free of charge," Apple said.
Apple advises iPhone 3G owners to charge their handsets by plugging them into computers or with a standard-sized Apple power adapter until the potentially problematic part is replaced.
Instructions for getting Apple adapters replaced were posted online at www.apple.com/support/usbadapter/exchangeprogram/.