The adapters were also included in the Apple World Travel Adapter Kit.
In an official statement, the company explained how to identify adapters that may be affected by the problem.
People were advised to stop using the adapters and bring them to an Apple shop for replacement.
Visit apple.com/support/ac-wallplug-adapter for information on how to identify and exchange affected adapters for the new, redesigned version.
source: www.techworm.net