If you purchased model A1300 of the European iPhone adapter between October 2009 and September 2012, then you may want to keep it as far away from an outlet as possible. Apple launched a replacement program for the faulty wall adapter after the company found out it overheats, potentially proving to be a safety risk.
The adapter, included with the iPhone 3GS, iPhone 4, and iPhone 4S, was replaced by model A1400 in 2012, which is not affected. Whether you purchased the European iPhone adapter separately, or it came bundled with the aforementioned iPhones, Apple wants you to make an appointment at your nearest Apple Store or Apple Authorized Service Provider to get it replaced. If neither one is close to you, you can contact Apple Technical Support.
This will likely be quite the undertaking for Apple, seeing as millions of the model A1300 adapters are out in the wild. Notable countries affected by the recall include Denmark, Egypt, France, Germany, Greece, India, Italy, Poland, Portugal, Russia, South Africa, Spain, and Turkey. You can check out the full list at Apple’s dedicated portal for the issue.