Apple now has two recall programs for AC wall plug adaptors. Check all your Apple-supplied power adaptors to see if they might be eligible for replacement.
The latest recall, announced today, is for 3-prong adaptors with UK square pins which were sold with Apple products for UK, Singapore and Hong Kong from 2003-2010, and additionally over that period in the Apple World Travel Adapter Kit. Their design is quite distinctive, and is shown in Apple’s announcement.
The danger with them is that they may break, exposing the user to the risk of electric shock. Apple doesn’t warn that they are inherently unsafe so long as they remain unbroken, though.
Apple also has a much older AC wall plug adaptor replacement programme which you may not have heard about. This concerns adaptors sold with Apple products for use in Continental Europe, Australia, New Zealand, Korea, Argentina and Brazil, and additionally in the Apple World Travel Adapter Kit, which shipped from 2003-2015. They have a similar risk of breakage, and when broken may expose the user to the risk of electric shock. Apple shows fuller details here.
Thanks to MacFormat magazine for the alert.