Apple has announced a voluntary recall on power adapters for AC wall plug adapters that shipped with Mac and iOS devices between 2003 and 2015.

 In very rare cases, affected Apple two-prong wall plug adapters may break and create a risk of electrical shock if touched.

The part in question is the piece that clips onto the large brick, it looks like this


If on the inside it has these markings, shown below, then it needs to be replaced.


If your adapter does match, then you can request a replacement online, or go to your local Apple Store or Authorised Apple Service Provider.

All information, including what to do, if you have paid for one can be found here  http://www.apple.com/au/support/ac-wallplug-adapter/